Add flock to openapi spec upload

Prevents a race condition if two PRs are merged in very quick
succession.

.github/workflows/ci-openapi.yml

@@ -174,6 +174,8 @@ jobs:
           debug: false
           script_stop: false
           script: |
+            (
+            flock -x -w 300 200
             TGT_DIR="/srv/repository/main/openapi"
             LAST_SPEC="$( ls -lt ${TGT_DIR}/unstable/ | grep 'jellyfin-openapi' | head -1 | awk '{ print $NF }' )"
             # If new and previous spec don't differ (diff retcode 0), remove incoming and finish
@@ -194,3 +196,4 @@ jobs:
                 sudo rm ${TGT_DIR}/jellyfin-openapi-unstable_previous.json
                 sudo ln -s unstable/${LAST_SPEC} ${TGT_DIR}/jellyfin-openapi-unstable_previous.json
             fi
+            ) 200>/run/openapi-unstable.lock