Make showRef with refs param public

BUG=414634331
PiperOrigin-RevId: 753308647
Change-Id: I936fffe1ce22b7d297d0d7eb465e0159a6491d58

Author: chris-campos

java/com/google/copybara/git/GitRepository.java

@@ -800,8 +800,11 @@ static String validateUrl(String url) throws RepoException, ValidationException
   /**
    * Execute show-ref git command in the local repository and returns a map from reference name to
    * GitReference(SHA-1).
+   *
+   * @param refs the refs to pass to the git show-ref command
+   * @return the result of git show-ref
    */
-  ImmutableMap<String, GitRevision> showRef(Iterable<String> refs) throws RepoException {
+  public ImmutableMap<String, GitRevision> showRef(Iterable<String> refs) throws RepoException {
     ImmutableMap.Builder<String, GitRevision> result = ImmutableMap.builder();
     CommandOutput commandOutput = gitAllowNonZeroExit(NO_INPUT,
         ImmutableList.<String>builder().add("show-ref").addAll(refs).build(),