Bump actions/cache from 4.0.0 to 4.0.2 in /actions/vellum-site-build

Bumps [actions/cache](https://github.com/actions/cache) from 4.0.0 to 4.0.2.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](actions/cache@13aacd8...0c45773)

---
updated-dependencies:
- dependency-name: actions/cache
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

actions/vellum-site-build/action.yml

@@ -16,7 +16,7 @@ runs:
 
   - name: Get cached NPM modules
     id: cache_npm_dependencies
-    uses: actions/cache@13aacd865c20de90d75de3b17ebe84f7a17d57d2    # v4.0.0
+    uses: actions/cache@0c45773b623bea8c8e75f6c82b208c3cf94ea4f9    # v4.0.2
     with:
       path: |
         .github/node_modules
@@ -43,7 +43,7 @@ runs:
 
   - name: Store generated web site
     id: cache_site
-    uses: actions/cache/save@13aacd865c20de90d75de3b17ebe84f7a17d57d2    # v4.0.0
+    uses: actions/cache/save@0c45773b623bea8c8e75f6c82b208c3cf94ea4f9    # v4.0.2
     with:
       path: website.zip
       key: website-${{ github.sha }}