build: serialize concurrent publish runs to fix google error

google can only handle one in-flight edit at a time, so only one
publish at a time. this allows concurrent publish workflow starts
(say on branch and main) and serializes them to work with google

Fixes ankidroid#15743

.github/workflows/publish.yml

@@ -8,6 +8,15 @@ on:
         required: false
         type: string
 
+
+# We want concurrency control to allow multiple runs, but serially
+# Otherwise if you run two publishes that upload to google at same time
+# (for instance on a release branch for beta, and main for alpha), google
+# will error as it can only handle one edit in publish account at once
+concurrency:
+  group: ${{ github.workflow }}
+  cancel-in-progress: false
+
 jobs:
   release_app:
     name: 'Release App'