Update build-jeckyll.yml - updated to v4

Updated to checkout and cache to v4

.github/workflows/build-jeckyll.yml

@@ -16,10 +16,10 @@ jobs:
           - 8080:8080
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       # Use GitHub Actions' cache to cache dependencies on servers
-      - uses: actions/cache@v3
+      - uses: actions/cache@v4
         with:
           path: vendor/bundle
           key: ${{ runner.os }}-gems-${{ hashFiles('**/Gemfile.lock') }}