Added solution to Leetcode Question - 7 | Reverse Integer

[himanshujaindev]

Question number - 7

Issue no.(must) - #7

Self Check(Tick After Making pull Request)

• This issue was assigned to me.
• One Change in one Pull Request
• My file is in proper folder (Name of folder should be Question number) (E.g. 120)
• I am following clean code and Documentation and my code is well linted with flake8.
• I have added README.md (With question description)
• I have added sufficient comments in my code

If issue was not assigned to you Please don't make a PR. It will marked as invalid.

[github-actions]

Congratulations!! 🎉 @nhimanshujain for making your first PR. We will review the changes soon and merge finally.😊 Do give a star ⭐ meanwhile if you like this project.