chore: improve PR template

Author: ldez

.github/PULL_REQUEST_TEMPLATE.md

@@ -5,6 +5,8 @@ WARNING:
 We use Dependabot to update dependencies (linters included).
 The updates happen at least automatically once a week (Sunday 11am UTC).
 
+Non-versioned dependencies are managed by the golangci-lint maintainers.
+
 No pull requests to update a linter will be accepted unless:
 you are the original author of the linter, AND there are important changes required (like a major version bump).