What techniques would you use to lure a player who is just there to bash stuff into role playing?

Don't. It will only result in an uncomfortable experience for both you and them. If they are having fun bashing stuff, that's perfectly fine. Don't try to force them to do something that they might not enjoy.

Agreed; if the player doesn't want to RP, don't try to shoehorn them into a playstyle they don't care for. 

However, if the player is nervous or unpracticed at RP and wants to try to grow in that area, you could ask them to describe how they bash stuff. Ask for flavor and flair. They clearly like combat, so gently nurture them to dive into it. Ask them where they aim, or what their spells look like. If they get a killing blow, as them if they do anything cool as the monster goes down - or turn the floor over to them entirely in a Mercer-style "how do you wanna do this?" Meet the player where they are and find some low-pressure areas where they can stretch their roleplay muscles by focusing on elements they like and feel comfortable with. 

I straight up told my players - role play is always an option. Even in the middle of a fight, you can attempt to communicate and find a non-violent solution. I also tell them they don't have to act or do voices if they don't want to, they can just describe to me what they are doing/saying - "I look him square in the eye, and tell him we are not his enemy, the BBEG asking him to put his life on the line is his real enemy." Everyone has their own level of comfort.

One thing I found was a roadblock to role play was rolling initiative. My players like role play - probably more than combat even - but even for them I find that saying 'roll for initiative' in an encounter is generally interpreted as 'role play over - start fighting'. I plan to solve that with a single initiative roll at the start of the session that is then used for the night. If you already have an initiative order ready to go when necessary, you aren't waving that red flag at the beginning of each encounter. It's a small thing, but psychologically I believe it'll have an impact.

Put a few situations in front of them where combat is quite obviously not the solution. Initiate the role play with a few NPCs - just a friendly shop keep passing the time of day. If they still insist on murderlizing their way through the town, have the world react accordingly. No city is going to put up with a group of maniacs wandering through killing all the shopkeeps and looting their stores, and the party won't stop being murder hobos if it always benefits them. In a situation where maybe they would ordinarily expect an automatic violent reaction, have the NPC react with roleplay. A guard may be completely friendly - so long as you don't approach the thing they are guarding. Even then, a guard will rarely just automatically attack - they'll offer warnings first "What are you doing? Get away from that." The guard could also be physically superior to them (sign post this), but happy to take a bribe. You control the tone of the table through the tone of your NPCs.

Always make them feel awesome when they get past something using roleplay instead of violence. Even if you planned it all upfront and sign-posted the shit out of it for their dumb asses, make them feel like they totally outsmarted you by talking their way around what you had planned as an epic fight. Sometimes I'll be inwardly smiling as I sigh and say something like "I can't believe this, but you've successfully conned your way past [creature]. Guess I won't be needing this" and put away a stat block. Outsmarting the DM in D&D feels like outsmarting God. If you make it awesome and badass to fight through swathes of orcs, but boring to deceive the Orcs into defecting to your side, then guess what they'll choose?

Be prepared though - pushing roleplay could mean they don't enjoy the game anymore. You then have to decide if you can have fun providing the kind of game they want. They aren't wrong to want a combat oriented game and you aren't wrong to want more roleplay. Not every DM is suited to every party, and the final solution to this problem could be amicable divorce.

Remember the reason the inspiration system exists is to reward good role play.  If this player notices they are constantly missing out on inspiration while other players are not (because they are role playing) maybe they can be coaxed that way.  

At the end of the day it is up to them though. 

 I concur with TheologyOfBagels, even if they don't enjoy RP, they will likely enjoy narrating the effects of killshot or a high-damaging attack, but if they don't want to RP, don't make them.

Quote from SireSamuel >>

Remember the reason the inspiration system exists is to reward good role play.  If this player notices they are constantly missing out on inspiration while other players are not (because they are role playing) maybe they can be coaxed that way.  

 That is coercion or bribery not coaxing. It's wrong to punish by denial just because they don't want to play the same way as somebody else. 

Quote from Wysperra >>

Quote from SireSamuel >>

Remember the reason the inspiration system exists is to reward good role play.  If this player notices they are constantly missing out on inspiration while other players are not (because they are role playing) maybe they can be coaxed that way.  

 That is coercion or bribery not coaxing. It's wrong to punish by denial just because they don't want to play the same way as somebody else. 

Inspiration is also just for when the players come up with something that is absolutely brilliant and makes you start improvising the rest of the session. Like locking themselves in a room to scape the dragon and burrowing out with all the treasure. I apply it not for RP, but for creativity and generally fun ideas.

Just like good writing: show, don’t tell.