Rename "PRIVATE_KEY" variable to "WALLET_PRIVATE_KEY"

[jule64]

I've just spent 1 hour in a Chainlink workshop struggling to start up hardhat because I assumed this variable was for the infura/alchemy private key.. I kept getting these "private key too short" error messages and even the bootcamp people didn't realise what the issue was.
Using a more explicit name for this variable could resolve any confusion as I imagine others might have faced this too..

[naman1402]

Can I work on this issue ?

[andrejrakic]

@NamanMohnani, of course, go for it! Thanks for raising this issue, @jule64

[naman1402]

@andrejrakic Apparently I can not make changes in the .env file, am I supposed to make changes in the .env.example file ?

[naman1402]

@andrejrakic I've submitted my PR kindly check on it.