chore: drop support for homebrew installs

fix: remove deps in homebrew

fix: failed gists due to NoneType

fix: homebrew rust dependency

chore: swap python version on homebrew

chore: drop python 3.8 and 3.9, codecov

feat: languages filter (closes #59)

feat: thread forking gists, fix log messages

fix: expand user-supplied location paths (closes #58)

fix: pygithub pin