Dependabot: check for updates of GitHub Actions.

Also switch test reporter action.

.github/dependabot.yml

@@ -0,0 +1,9 @@
+# Please see the documentation for all configuration options:
+# https://docs.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
+
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"

.github/workflows/build-and-test.yml

@@ -8,16 +8,20 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
-      - uses: actions/setup-java@v3
+      - name: Check out
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+      - name: Set up JDK 11
+        uses: actions/setup-java@0ab4596768b603586c0de567f2430c30f5b0d2b0 # v3.13.0
         with:
           distribution: 'temurin'
           java-version: '11'
           cache: 'maven'
       - name: Build with Maven
         run: mvn --batch-mode -show-version --update-snapshots --errors package
       - name: Publish Unit Test Results
-        uses: EnricoMi/publish-unit-test-result-action@v2
+        uses: dorny/test-reporter@afe6793191b75b608954023a46831a3fe10048d4 # v1.7.0
         if: always() # also run if build step failed
         with:
-          junit_files: target/surefire-reports/*.xml
+          name: JUnit Report
+          path: target/surefire-reports/*.xml
+          reporter: java-junit