Ignore SLF4J 2.x in Dependabot

Maven 3 exports slf4j-api 1.7.x to plugins, so this component stays on
SLF4J 1.7.x. See apache/maven-parent#623.

Author: slachiewicz

.github/dependabot.yml

@@ -30,6 +30,9 @@ updates:
     ignore:
       - dependency-name: "org.mockito:*"
         versions: [ "[5.0.0,)" ]
+      # Maven 3 so use SLF4J 1.7.x
+      - dependency-name: "org.slf4j:*"
+        versions: [">= 2.0.0"]
 
   - package-ecosystem: "github-actions"
     directory: "/"