Ignore Maven Core update

Author: slawekjaranowski

.github/dependabot.yml

@@ -23,6 +23,8 @@ updates:
     time: '04:00'
   open-pull-requests-limit: 10
   ignore:
+    # Ignore Maven Core updates
+    - dependency-name: "org.apache.maven:*"
     # ignore Java 8+ dependencies
     - dependency-name: org.mockito:mockito-core
       versions:
@@ -36,4 +38,4 @@ updates:
     # Ignore Maven 3.2.1+
     - dependency-name: org.apache.maven.plugin-testing:maven-plugin-testing-tools
       versions:
-        - ">=3.2.0"
+        - ">=3.2.0"