Revert to empty version and update repo metadata (#1975)

**What type of PR is this?**

Bug fix

**What package or component does this PR mostly affect?**

BCR

**What does this PR do? Why is it needed?**

The new style also isn't supported by Publish to BCR and a fix is in
flight: bazel-contrib/publish-to-bcr#175

**Which issues(s) does this PR fix?**

Fixes #

**Other notes for review**

.bcr/metadata.template.json

@@ -1,5 +1,5 @@
 {
-  "homepage": "https://github.com/bazelbuild/bazel-gazelle",
+  "homepage": "https://github.com/bazel-contrib/bazel-gazelle",
   "maintainers": [
     {
       "email": "[email protected]",
@@ -18,7 +18,7 @@
     }
   ],
   "repository": [
-      "github:bazelbuild/bazel-gazelle"
+      "github:bazel-contrib/bazel-gazelle"
   ],
   "versions": [],
   "yanked_versions": {}

MODULE.bazel

@@ -1,7 +1,8 @@
 module(
     name = "gazelle",
+    # Updated by the Publish to BCR app.
+    version = "",
     repo_name = "bazel_gazelle",
-    # version is set by the Publish to BCR app.
 )
 
 bazel_dep(name = "bazel_features", version = "1.9.1")