Un-hack prerelease builds

.github/workflows/preview-release.yaml

@@ -6,7 +6,7 @@ on:
       - completed
   push:
     # Run only on trunk pushes that aren't a new tag release
-    branches: [trunk, fix-aarch-builds]
+    branches: [trunk]
     tags-ignore: "*"
 
 env:
@@ -64,6 +64,11 @@ jobs:
           override: true
           profile: minimal
           target: aarch64-unknown-linux-gnu
+      - uses: actions/cache@v2
+        with:
+          path: |
+            librubyfmt/ruby_checkout
+          key: ${{ runner.os }}-${{matrix.target}}-ruby-v1-${{ hashFiles('.git/modules/librubyfmt/ruby_checkout/HEAD') }}
       - if: runner.os == 'macOS'
         run: |
           brew install automake bison