Bump maven-gh-actions-shared to v4

Author: slachiewicz

.github/workflows/maven-verify.yml

@@ -24,4 +24,4 @@ on:
 jobs:
   build:
     name: Verify
-    uses: apache/maven-gh-actions-shared/.github/workflows/maven-verify.yml@v2
+    uses: apache/maven-gh-actions-shared/.github/workflows/maven-verify.yml@v4