Bump dependabot limit (#3416)

We have currently 5 open dependabot PRs that are blocked mostly by Java 17 or each other. This enables to have more PRs open to bump other dependencies.

Author: Fokko

.github/dependabot.yml

@@ -29,3 +29,4 @@ updates:
     schedule:
       interval: "weekly"
       day: "sunday"
+    open-pull-requests-limit: 50