build: actions/cache@v4

Author: loki-cmu

.github/workflows/rust.yml

@@ -22,7 +22,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v2
       - name: Cache Cargo dependencies
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: ~/.cargo
           key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}