PULL_REQUEST_TEMPLATE.md

What this PR does / why we need it:

Checklist

[Place an '[x]' (no spaces) in all applicable fields. Please remove unrelated fields.]

• Title of the PR starts with chart name (e.g. [mychartname])
• Chart Version bumped for the respective charts
• Changelog updated for the charts with version updates.
• Variables are documented in the README.md (or README.tpl in some charts)
• Check GithubAction checks (like lint) to avoid merge-check stoppers

Check Contribution guidelines in README.md for more insight.