docs: remove broken badge links (tediousjs#1672)

[BrandonNoad]

Before submitting a PR :

1. Ensure your fork is created from master branch of the repository.
2. Run npm install in the root folder.
3. After bug fix/code change, ensure all the existing tests and new tests (if any) pass (npm run-script test-all). During development, to run individual test use node_modules/nodeunit test/<test_file.js> -t <test_name>.
4. Build the driver (npm run build).
5. Run eslint and flow typechecker (npm run lint).
6. Run commitlint (node_modules/.bin/commitlint --from origin/master --to HEAD). Refer commit conventions and commit rules.

Thank you for Contributing!