Dependabot: check for go dependency security updates too (#3660)

## Description:

Let dependabot also check for security updates for go dependencies
periodically.

Even though we only use go in map-generator and it's only one dependency
currently, still good to catch security updates.

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

## Please put your Discord username so you can be contacted if a bug or
regression is found:

tryout33

---------

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

.github/dependabot.yml

@@ -9,7 +9,16 @@ updates:
     groups:
       updates:
         applies-to: version-updates
-        patterns: ["*"] #wildcard, needs brackets as bugfix apparently
+        patterns: ["*"] # wildcard, needs brackets as bugfix apparently
       security:
         applies-to: security-updates
         patterns: ["*"]
+  - package-ecosystem: "gomod"
+    directory: "/map-generator"
+    schedule:
+      interval: "monthly"
+    open-pull-requests-limit: 0 # exclude version updates
+    groups:
+      golang:
+        applies-to: security-updates
+        patterns: ["*"]