ci-automation: Allow git to work on directory owned by other user

The get_git_channel function failed to work which resulted in the
Alpha release job skipping the AWS publishing for the Alpha channel
because it defaulted to the developer channel as fallback when git
rejected to work on the directory owned by the build user while running
as root user. A new version of git caused this behavior change and also
prints an error message that explains to have to set safe.directory.

Set the git config entry safe.directory for the /work path when
entering the mantle container where git runs as root while working on
the directory owned by the build user.

ci-automation/release.sh

@@ -208,7 +208,7 @@ function _release_build_impl() {
 
     touch sdk_container/.env # This file should already contain the required credentials as env vars
     docker run --pull always --rm --name="${container_name}" --net host \
-      -w /work -v "$PWD":/work "${mantle_ref}" bash -c "source ci-automation/release.sh; _inside_mantle"
+      -w /work -v "$PWD":/work "${mantle_ref}" bash -c "git config --global --add safe.directory /work && source ci-automation/release.sh && _inside_mantle"
     # Push flatcar_production_ami_*txt and flatcar_production_ami_*json to the right bincache folder
     for arch in amd64 arm64; do
       sudo chown -R "$USER:$USER" "aws-${arch}"

ci-automation/test.sh

@@ -186,7 +186,7 @@ function _test_run_impl() {
         touch sdk_container/.env
         docker run --pull always --rm --name="${container_name}" --privileged --net host -v /dev:/dev \
           -w /work -v "$PWD":/work "${mantle_ref}" \
-         bash -c "set -o noglob && source sdk_container/.env && ci-automation/vendor-testing/${image}.sh \
+         bash -c "set -o noglob && git config --global --add safe.directory /work && source sdk_container/.env && ci-automation/vendor-testing/${image}.sh \
                 \"${work_dir}\" \
                 \"${tests_dir}\" \
                 \"${arch}\" \
@@ -196,6 +196,7 @@ function _test_run_impl() {
         set -e
         rm -f "${work_dir}/first_run"
 
+        # Note: git safe.directory is not set in this run as it does not use git
         docker run --pull always --rm --name="${container_name}" --privileged --net host -v /dev:/dev \
           -w /work -v "$PWD":/work "${mantle_ref}" \
             ci-automation/test_update_reruns.sh \