Updated tiny punctuation marks in README.md

[github-actions[bot]]

Hi @sohamp19! Thank you for opening your first Pull Request. Please add any information we might need in the comments, make sure any issues you are resolving are linked ( what is this? ), and one of our project maintainers will review it soon. Thank you for making Power BI Theme Templates better!

[MattRudy]

Great work github-actions bot, and thanks @sohamp19 ! This PR fixes #79, and is related to (but does not close) issue 78.

Confirmed:

• New Issue response works as expected
• New PR response works as expected
• Link in New PR response works
• Workflows to validate JSONs and Docs correctly wait for a first-time contributor's PR until approved
• Workflows to validate JSONs and Docs both pass as expected
• Merging the PR is blocked until Review is completed
• Everything passes once the above steps are completed

Success!