Use replacement git/http external repo rules
Use replacement git/http external repo rules

This update moves away from the deprecated external repo rules to use their recommended replacements. `rules_apple` uses the new rules too. See: https://docs.bazel.build/versions/master/be/workspace.html#git_repository

Closes #74.

PiperOrigin-RevId: 217702003

bazelbuild/rules_swift,bazelbuild/rules_swift