Update obsolete cache storage in GitHub workflow

https://github.blog/changelog/2024-12-05-notice-of-upcoming-releases-and-breaking-changes-for-github-actions/#actions-cache-v1-v2-and-actions-toolkit-cache-package-closing-down

Author: fyrbach

.github/workflows/build.yml

@@ -16,7 +16,7 @@ jobs:
         with:
           java-version: ${{ matrix.java }}
       - name: Cache Maven packages
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: ~/.m2
           key: ${{ runner.os }}-m2-${{ hashFiles('**/pom.xml') }}

pom.xml

@@ -97,7 +97,7 @@
     </repositories>
 
     <properties>
-        <pgpVerifyKeysVersion>1.7.12</pgpVerifyKeysVersion>
+        <pgpVerifyKeysVersion>1.8.3</pgpVerifyKeysVersion>
         <wrenBuildToolsVersion>1.2.0</wrenBuildToolsVersion>
 
         <!-- Source code has to be Java 8 compliant (code base is not JPMS ready) -->