bazlets: Replace native.git_repository with skylark rule

The native.git_repository rule does not work properly when invoked in a
`git submodule foreach` command. Bazel will deprecate the native rules
anyway, so replace with skylark's git_repository.

See [1] for context.

[1] https://github.com/bazelbuild/bazel/issues/6358#issuecomment-429103745

Change-Id: I671b0d2a136367ad74d4a6f0aa14f2ae0cf01cc3
1 file changed