Update CI

Author: cowtowncoder

.github/dependabot.yml

@@ -0,0 +1,10 @@
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "monthly"
+    groups:
+      github-actions:
+        patterns:
+          - "*"

.github/workflows/main.yml

@@ -17,14 +17,14 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        java_version: ['8', '11', '17', '21']
-        os: ['ubuntu-20.04']
+        java_version: ['8', '17', '21']
+        os: ['ubuntu-22.04']
     env:
       JAVA_OPTS: "-XX:+TieredCompilation -XX:TieredStopAtLevel=1"
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b # v4.1.4
     - name: Set up JDK
-      uses: actions/setup-java@v3
+      uses: actions/setup-java@99b8673ff64fbf99d8d325f52d9a5bdedb8483e9 # v4.2.1
       with:
         distribution: 'temurin'
         java-version: ${{ matrix.java_version }}