Fix CI badge in README and docs

[Anurag-Nagpal]

Description

Kindly take a look at CONTRIBUTING.md.

Please describe the purpose of this pull request. Reference and link to any relevant issues or pull requests.

Checklist

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't any other open Pull Requests for the required change?
• Does your submission pass pre-commit? ($ pre-commit run --all-files or $ nox -s lint)
• Does your submission pass tests? ($ pytest or $ nox -s tests)
• Does the documentation build with your changes? ($ cd docs; make clean; make html or $ nox -s docs)
• Does your submission pass the doctests? ($ xdoctest ./src/vector or $ nox -s doctests)

Before Merging

• Summarize the commit messages into a brief review of the Pull request.

[Saransh-cpp]

Hi, @Anurag-Nagpal. Thanks for working on this!

#386 fixes this, but please feel free to take a look at other good first and hacktoberfest issues 🙂