CI: Cache cross binary

Author: acj

.github/workflows/build.yml

@@ -34,6 +34,12 @@ jobs:
       - name: Install Rust
         uses: dtolnay/rust-toolchain@4be7066ada62dd38de10e7b70166bc74ed198c30 # stable branch
 
+      - name: Cache cross binary
+        uses: actions/cache@v4
+        with:
+          path: ~/.cargo/bin/cross
+          key: cross-51f46f296253d8122c927c5bb933e3c4f27cc317
+
       - name: Install cross
         run: |
           if [ ! -f "$HOME/.cargo/bin/cross" ]; then