Update all Pages workflows to actions/cache@v4 for node20 compliance

Author: JamesMGreene

pages/gatsby.yml

@@ -65,7 +65,7 @@ jobs:
           # You may remove this line if you want to manage the configuration yourself.
           static_site_generator: gatsby
       - name: Restore cache
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: |
             public

pages/nextjs.yml

@@ -62,7 +62,7 @@ jobs:
           # You may remove this line if you want to manage the configuration yourself.
           static_site_generator: next
       - name: Restore cache
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: |
             .next/cache

pages/nuxtjs.yml

@@ -60,7 +60,7 @@ jobs:
           # You may remove this line if you want to manage the configuration yourself.
           static_site_generator: nuxt
       - name: Restore cache
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: |
             dist