feat: Add additional check of screenshot for dashboard updates (strimzi#3307)

* feat: Add additional check of screenshot for dashboard updates

Signed-off-by: Samuel Hawker <[email protected]>

* fix: Reword

Signed-off-by: Samuel Hawker <[email protected]>

Author: samuel-hawker

.github/PULL_REQUEST_TEMPLATE.md

@@ -22,4 +22,5 @@ _Please go through this checklist and make sure all applicable tasks have been d
 - [ ] Try your changes from Pod inside your Kubernetes and OpenShift cluster, not just locally
 - [ ] Reference relevant issue(s) and close them after merging
 - [ ] Update CHANGELOG.md
+- [ ] Supply screenshots for visual changes, such as Grafana dashboards