added the solution to the problem caesar cipher

[sam-mittal]

Fixes #

Checklist

• [x] I have read the [Contribution Guide] and my PR follows them.
• [x] My branch is up-to-date with the master branch.
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] I have added necessary documentation (if appropriate)
• [x] The contents added are completelt original and have no copyright issues.

Short description of what this resolves:

Changes proposed in this pull request:

-this pr adds a solution to new problem caesar cipher