Add Maven Caching.

.github/workflows/antora-site.yml

@@ -46,6 +46,11 @@ jobs:
           package.json
           package-lock.json
         key: ${{ runner.os }}-nodejs-${{ hashFiles('pom.xml') }}
+    - name: Cache Maven
+      uses: actions/cache@v3
+      with:
+        path: ~/.m2
+        key: ${{ runner.os }}-maven
     - name: Run Antora
       run: ./mvnw -B antora -Dspring-data.module=${{ github.event.inputs.module }}
     - name: Archive results