overturemaps 0.20.0 (new formula)

[jjcfrancisco]

• Have you followed the guidelines for contributing?
• Have you ensured that your commits follow the commit style guide?
• Have you checked that there aren't other open pull requests for the same formula update/change?
• Have you built your formula locally with HOMEBREW_NO_INSTALL_FROM_API=1 brew install --build-from-source overturemaps?
• Is your test running fine brew test overturemaps?
• Does your build pass brew audit --strict overturemaps (after doing HOMEBREW_NO_INSTALL_FROM_API=1 brew install --build-from-source overturemaps)? If this is a new formula, does it pass brew audit --new overturemaps?