add rust build caching

.forgejo/workflows/cargo.yml

@@ -8,15 +8,17 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: https://github.com/dtolnay/rust-toolchain@stable
+      - uses: https://github.com/Swatinem/rust-cache@v2
       - run: cargo test --all-features
   bench:
     name: Run Benchmarks
     runs-on: ubuntu-latest
     steps:
-      - uses: https://github.com/dtolnay/rust-toolchain@stable
       - uses: actions/checkout@v4
         with:
           fetch-depth: 2
+      - uses: https://github.com/dtolnay/rust-toolchain@stable
+      - uses: https://github.com/Swatinem/rust-cache@v2
       - run: git checkout HEAD~
       - run: cargo bench
       - run: git checkout master