Improve CI (#78)

Author: aurexav

.github/workflows/checks.yml

@@ -25,13 +25,16 @@ jobs:
       matrix:
         action: [clippy, fmt, test]
     steps:
-      - name: Setup build environment
-        run: rustup toolchain install nightly --profile minimal
       - name: Fetch latest code
         uses: actions/checkout@v3
+      - name: Setup build environment
+        if: matrix.action != 'fmt'
+        run: rustup show
       - uses: Swatinem/rust-cache@v2
+        if: matrix.action != 'fmt'
         with:
           prefix-key: ${{ env.CACHE_VERSION }}
+          key: ${{ matrix.action }}
       - name: Cargo clippy
         if: matrix.action == 'clippy'
         uses: actions-rs/clippy-check@v1