update actions

Author: Adam-

.github/workflows/CI.yml

@@ -4,26 +4,18 @@ on: [ push, pull_request ]
 
 jobs:
   build:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
-
-      - name: Cache
-        uses: actions/cache@v2
-        with:
-          path: |
-            ~/.m2/repository
-          key: ${{ runner.os }}-cache-${{ hashFiles('**/pom.xml') }}
-          restore-keys: |
-            ${{ runner.os }}-cache-
+        uses: actions/checkout@v4
 
       - name: Set up JDK 11
         uses: actions/setup-java@v2
         with:
           distribution: adopt
           java-version: 11
+          cache: 'maven'
 
       - name: Build
         run: mvn verify --settings ci/settings.xml