[Backport v1.x] Add a more helpful summary to automated backport PRs (#…

…238)

## Summary

This is an automated backport of
9c8a9d4 from #237 to **v1.x**. It was
created because a maintainer labeled #237 with the <kbd>[backport
v1.x](https://github.com/inngest/inngest-js/labels/backport%20v1.x)</kbd>
label.

When this PR is merged, it will create a PR to release **v1.x** if a
changeset is found.

## Related

- #237

Co-authored-by: Jack Williams <jack@inngest.com>

.github/workflows/backport.yml

@@ -25,3 +25,13 @@ jobs:
       - uses: tibdex/backport@v2
         with:
           github_token: ${{ secrets.CHANGESET_GITHUB_TOKEN }}
+          body_template: |-
+            ## Summary
+
+            This is an automated backport of <%= mergeCommitSha %> from #<%= number %> to **<%= base %>**. It was created because a maintainer labeled #<%= number %> with the <kbd>[backport <%= base %>](https://github.com/inngest/inngest-js/labels/backport%20<%= base %>)</kbd> label.
+
+            When this PR is merged, it will create a PR to release **<%= base %>** if a changeset is found.
+
+            ## Related
+
+            - #<%= number %>