Return repo_metadata from repository rules (#152)

To satisfy https://github.com/bazelbuild/bazel/pull/30202

private/globals_repo.bzl

diff --git a/private/globals_repo.bzl b/private/globals_repo.bzl
index 34b0713..d9b8f5e 100644
--- a/private/globals_repo.bzl
+++ b/private/globals_repo.bzl
@@ -42,6 +42,9 @@
     lines.append(")")
 
     rctx.file("globals.bzl", "\n".join(lines))
+    if hasattr(rctx, "repo_metadata"):
+        return rctx.repo_metadata(reproducible = False)
+    return None
 
 globals_repo = repository_rule(
     _globals_repo_impl,

private/version_repo.bzl

diff --git a/private/version_repo.bzl b/private/version_repo.bzl
index a82b558..323d760 100644
--- a/private/version_repo.bzl
+++ b/private/version_repo.bzl
@@ -16,6 +16,9 @@
 """,
     )
     rctx.file("version.bzl", "version = '" + native.bazel_version + "'")
+    if hasattr(rctx, "repo_metadata"):
+        return rctx.repo_metadata(reproducible = False)
+    return None
 
 version_repo = repository_rule(
     _version_repo_impl,