Add GitHub pull request template

[d33bs]

It'd be helpful to add a pull request template which can be used to define common PR author needs. For example:

• Pull request description
• Closes / resolves issue #
• "I have checked that there are no other pull requests already opened which address this issue or feature."

[AAYUSH-SPIDEY-SHARMA]

Hi, I would like to work on this issue. Could you please assign it to me?

[d33bs]

Sure thing, please feel free make a contribution here. Thanks @AAYUSH-SPIDEY-SHARMA !

[ANJALINITA]

Hi, I would like to work on this issue. Could you please assign it to me?