Remove caching step in validation workflow

.github/workflows/validate.yml

@@ -21,19 +21,6 @@ jobs:
         override: true
         components: rustfmt, clippy
 
-    - 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: validate-1m-linux
       env:
         CC: 'gcc'