TEMP: let this branch save caches

.github/workflows/build.yml

@@ -139,7 +139,7 @@ jobs:
           prefix-key: "v2026.11-rust"
           # Only main saves caches. The repository can keep 10 GB of caches, and the ones saved by pull
           # requests and other branches were mostly copies of main's that pushed other caches out.
-          save-if: ${{ github.ref == 'refs/heads/main' }}
+          save-if: ${{ github.ref == 'refs/heads/main' || github.ref == 'refs/heads/ci/build-speed' }}
       # End Enable Rust Caching
 
       # Run cargo tests