Call out that issue number should be in PR title

[cjellick]

Signed-off-by: Craig Jellick craig@acorn.io

Checklist

• All relevant issues are referenced in this PR
• The title of this PR would make a good line in Acorn's Release Note's Changelog
• Commits follow contributing guidance.
• Automated tests added to cover the changes. If tests couldn't be added, an explanation is provided in the Verification and Testing section
• Changes to user-facing functionality, API, CLI, and upgrade impacts are clearly called out in PR description

[ibuildthecloud]

What is an example of how to put the issue in the title. Just the number? Like Normal commit message #1120

[cjellick]

Example:
#1199

The upside is that when we generate the changelog in the release notes, it uses PR titles and the issue is there as a link. som examples here:
https://github.com/acorn-io/acorn/releases/tag/v0.5.1

The downside is that when you're looking at a PR, it looks a little cluttered.