fix: bind maven local repository in docker environment (#10967)

* fix: bind home dir in docker run

* update config for testing

* chore: generate libraries at Fri Jun 14 14:48:27 UTC 2024

* restore config

* Revert "restore config"

This reverts commit bb6370c.

* restore config

* restore change

* add comments

---------

Co-authored-by: cloud-java-bot <cloud-java-bot@google.com>

.github/scripts/hermetic_library_generation.sh

@@ -17,6 +17,7 @@ set -e
 # 1. git
 # 2. gh
 # 3. docker
+# 4. mvn
 
 # The parameters of this script is:
 # 1. target_branch, the branch into which the pull request is merged.
@@ -88,12 +89,15 @@ fi
 git show "${target_branch}":"${generation_config}" > "${baseline_generation_config}"
 config_diff=$(diff "${generation_config}" "${baseline_generation_config}" || true)
 
+# get .m2 folder so it's mapped into the docker container
+m2_folder=$(dirname "$(mvn help:evaluate -Dexpression=settings.localRepository -q -DforceStdout)")
+
 # run hermetic code generation docker image.
 docker run \
   --rm \
   -u "$(id -u):$(id -g)" \
   -v "$(pwd):${workspace_name}" \
-  -v "$HOME"/.m2:/home/.m2 \
+  -v "${m2_folder}":/home/.m2 \
   gcr.io/cloud-devrel-public-resources/java-library-generation:"${image_tag}" \
   --baseline-generation-config-path="${workspace_name}/${baseline_generation_config}" \
   --current-generation-config-path="${workspace_name}/${generation_config}"