Simplify dependabot: single maven group, monthly cadence (#347)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: infeo <9036915+infeo@users.noreply.github.com>

Author: Copilot

.github/dependabot.yml

@@ -3,41 +3,15 @@ updates:
   - package-ecosystem: "maven"
     directory: "/"
     schedule:
-      interval: "weekly"
-      day: "monday"
-      time: "06:00"
-      timezone: "Etc/UTC"
+      interval: "monthly"
     ignore:
       # due to https://github.com/fabriciorby/maven-surefire-junit5-tree-reporter/issues/68
       - dependency-name: "org.apache.maven.plugins:maven-surefire-plugin"
         versions: ["3.5.4", "3.5.5"]
     groups:
-      java-test-dependencies:
-        patterns:
-          - "org.junit.jupiter:*"
-          - "org.mockito:*"
-          - "org.hamcrest:*"
-          - "com.google.jimfs:jimfs"
-      maven-build-plugins:
-        patterns:
-          - "org.apache.maven.plugins:*"
-          - "org.jacoco:jacoco-maven-plugin"
-          - "org.owasp:dependency-check-maven"
-          - "org.sonatype.central:central-publishing-maven-plugin"
-          - "me.fabriciorby:maven-surefire-junit5-tree-reporter"
-      java-production-dependencies:
+      maven-dependencies:
         patterns:
           - "*"
-        exclude-patterns:
-          - "org.apache.maven.plugins:*"
-          - "org.jacoco:jacoco-maven-plugin"
-          - "org.owasp:dependency-check-maven"
-          - "org.sonatype.central:central-publishing-maven-plugin"
-          - "me.fabriciorby:maven-surefire-junit5-tree-reporter"
-          - "org.junit.jupiter:*"
-          - "org.mockito:*"
-          - "org.hamcrest:*"
-          - "com.google.jimfs:jimfs"
 
 
   - package-ecosystem: "github-actions"