[FEAT] Maintainer shall be able to request for stars politely

[Varun-Kolanu]

• On successful merging of PR, along with the thank you note, the maintainer can request the contributor to star the repo, like "Thank you for your contribution! If you liked the project feel free to star the repo so that this can be discovered more easily and benefit open source community"
• The message should be configurable
• The bot should check whether the contributor starred the repo or not. Only if the user didn't star, maintainer shall ask
• Shall be done after [FEAT] Thank you note on PR getting merged  #9

[issue-assigner]

Comment '@issue-assigner claim' to get this issue assigned or '@issue-assigner abandon' to get this issue unassigned.