pmd/.github/PULL_REQUEST_TEMPLATE.md

Please, prefix the PR title with the language it applies to within brackets, such as [java] or [apex]. If not specific to a language, you can use [core]

Before submitting a PR, please check that:

• The PR is submitted against master. The PMD team will merge back to support branches as needed.
• mvn test passes.
• mvn checkstyle:check passes. Check this for more info

PR Description: