fix: serialize rust cache uploads

.gitea/actions/rust-cache/action.yml

@@ -13,7 +13,7 @@ inputs:
     required: false
   cache-version:
     description: Cache format version. Bump this to avoid reusing stale or partial cache entries.
-    default: v2
+    default: v3
     required: false
 
 outputs:
@@ -48,6 +48,7 @@ runs:
       id: cache-restore
       env:
         ACTIONS_CACHE_SERVICE_V2: "0"
+        CACHE_UPLOAD_CONCURRENCY: "1"
       uses: https://gitea.com/actions/cache@v3
       with:
         path: |