github: update pull_request_template

.github/pull_request_template.md

@@ -2,4 +2,7 @@
 
 - [ ] Run `helm lint` on the chart dir.
 - [ ] (Update) Bump the `Chart.yaml` version before merging, to release it as a new version.
+- [ ] (Update) Replace the `annotations` on the `Chart.yaml` with:
+ - `artifacthub.io/changes` - the changes introduced on the PR [with the appropiate format](https://artifacthub.io/docs/topics/annotations/helm/#supported-annotations).
+ - `artifacthub.io/images` - the updated tag on the `cs3org/revad` image.
 - [ ] (Update) If the PR includes new configurable parameters in the chart's `values.yaml`. Add documentation in the appropiate README.