cd.yaml: install rust toolchain with its caching

.gitea/workflows/cd.yaml

@@ -6,6 +6,23 @@ jobs:
     name: cargo build
     runs-on: ubuntu-latest
     steps:
+      - name: Restore cached Primes
+        id: cache-toolchain
+        uses: actions/cache/restore@v4
+        with:
+          path: |
+            ~/.rustup/toolchains
+          key: ${{ runner.os }}-rust-toolchain
+      - name: Install minimal stable with clippy and rustfmt
+        uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: stable
+      - uses: actions/cache/save@v4
+        with:
+          path: |
+            ~/.rustup/toolchains
+          key: ${{ steps.cache-toolchain.outputs.cache-primary-key }}
       - uses: actions/checkout@v4
       - run: cargo build --release --target x86_64-unknown-linux-gnu
       - name: Upload Release Binary