Possible improvements to the pa11y plugin

[cantsin]

Feature suggestion

In #3752 , we improved the speed of pa11y runs dramatically. But there are still some things we could do here.

Additional improvements

These improvements are not prioritized yet.

• Figure out how to escape the body text of the GitHub issue. This involves editing the repository_dispatch GitHub workflow file. This is a “nice to have” feature because the output of the pa11y scan can have HTML and if the body isn’t wrapped in backticks it causes the HTML to be rendered which isn’t very helpful. Here’s an example, the ID shown there should actually say <h2 id="test">ID</h2>
• Implement some logic in the workflow file to find a previous failed pa11y scan issue (using the gh issue tool and scanning for the tags nightly-pa11y-scan-failed,type:accessibility and compare the issue body of the previous issue to the new one coming in and take the appropriate action. The goal of this was only have one issue open at a time that represents a unique failure. We should always have an issue open for each unique failure but not have multiple issues open for the same failure that occurs multiple days in a row.

[beechnut]

@cantsin This has already been taken care of in https://github.com/18F/18f.gsa.gov/issues/3875

[cantsin]

Thank you @beechnut ; updated the issue to reflect that we have possible improvements we can do here.