Merge pull request #2689 from josiahaltschuler/add-period-to-sentence

Add period to end of sentence

CONTRIBUTING.md

@@ -63,7 +63,7 @@ Here are a few things you can do that will increase the likelihood of your pull
     You can start a release by triggering this workflow via [workflow dispatch](https://github.com/github/codeql-action/actions/workflows/update-release-branch.yml).
 1. The workflow run will open a pull request titled "Merge main into releases/v3". Follow the steps on the checklist in the pull request. Once you've checked off all but the last two of these, approve the PR and automerge it.
 1. When the "Merge main into releases/v3" pull request is merged into the `releases/v3` branch, a mergeback pull request to `main` will be automatically created. This mergeback pull request incorporates the changelog updates into `main`, tags the release using the merge commit of the "Merge main into releases/v3" pull request, and bumps the patch version of the CodeQL Action. 
-1. If a backport to an older major version is required, a pull request targeting that version's branch will also be automatically created
+1. If a backport to an older major version is required, a pull request targeting that version's branch will also be automatically created.
 1. Approve the mergeback and backport pull request (if applicable) and automerge them.
 
 Once the mergeback and backport pull request have been merged, the release is complete.