ci(safe-settings): add npm caching for safe-settings

Author: dafyddj

.github/workflows/safe-settings.yml

@@ -20,7 +20,7 @@ jobs:
       SAFE_SETTINGS_VERSION: 2.1.18
 
       # Path on GHA runner box where safe-settings code downloaded to:
-      SAFE_SETTINGS_CODE_DIR: ${{ github.workspace }}/.safe-settings-code
+      SAFE_SETTINGS_CODE_DIR: .safe-settings-code
     steps:
       # Self-checkout of 'admin' repo for access to safe-settings deployment configuration
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
@@ -35,6 +35,10 @@ jobs:
           path: ${{ env.SAFE_SETTINGS_CODE_DIR }}
           persist-credentials: false
       - uses: actions/setup-node@6044e13b5dc448c55e2357c09f80417699197238 # v6.2.0
+        with:
+          cache: npm
+          cache-dependency-path: ${{ env.SAFE_SETTINGS_CODE_DIR }}/package-lock.json
+          node-version-file: ${{ env.SAFE_SETTINGS_CODE_DIR }}/.nvmrc
       - run: npm install
         working-directory: ${{ env.SAFE_SETTINGS_CODE_DIR }}
       - name: Run Safe-Settings Full-Sync