Update dependabot.yml

Remove restriction on the Spring framework version; we are already using version 6.

Author: veithen

.github/dependabot.yml

@@ -29,10 +29,6 @@ updates:
       - dependency-name: "org.apache.maven.plugins:maven-plugin-plugin"
         versions:
         - "3.6.2"
-      # Spring 6 requires Java 17
-      - dependency-name: "org.springframework:*"
-        versions:
-          - ">= 6.0.0"
     open-pull-requests-limit: 15
   - package-ecosystem: "github-actions"
     directory: "/"