Pin Swatinem/rust-cache action to a full commit SHA

Author: JohnTitor

action.yml

@@ -212,7 +212,7 @@ runs:
 
     - name: Setup Rust Caching
       if: inputs.cache == 'true'
-      uses: Swatinem/rust-cache@v2
+      uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
       with:
         workspaces: ${{inputs.cache-workspaces}}
         cache-directories: ${{inputs.cache-directories}}