updated README.md

[VenkataBhaskarr]

Corrected some grammatical mistakes in README.md (How we built it section)

Check List (Check all the boxes which are applicable)

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• All new and existing tests passed.
• This PR does not contain plagiarized content.
• The title of my pull request is a short description of the requested changes.

Screenshots

After

Before