cache action

.github/workflows/rust_fmt_auto_build_test.yml

@@ -16,6 +16,18 @@ jobs:
 
     steps:
     - uses: actions/checkout@v4
+    - name: Set up cargo cache
+      uses: actions/cache@v3
+      continue-on-error: false
+      with:
+        path: |
+          ~/.cargo/bin/
+          ~/.cargo/registry/index/
+          ~/.cargo/registry/cache/
+          ~/.cargo/git/db/
+          target/            
+        key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
+        restore-keys: ${{ runner.os }}-cargo-
     - name: Fmt
       run: cargo fmt -- --check
     - name: Install cargo-auto