440 update GitHub actions

[ekraffmiller]

What this PR does / why we need it: Updates Github Action triggers for Chromatic and test builds

Which issue(s) this PR closes:

Closes #440

Special notes for your reviewer:
New triggers for the actions:

• chromatic and chromatic-design-system: all pull_request events
• test, lint and accessibility: push events

A push on a PR branch generates both a 'push' event and a pull request 'synchronize' event. So the test actions are not triggered on a push event, only on PR open and re-open. This will reduce the duplicate Github actions that we have been seeing.

For the Chromatic actions, if this change still isn't enough to stop us from hitting the monthly limit, another thing we could think of doing is make the action 'on demand', so it would only be manually triggered when it is necessary for review.

Suggestions on how to test this:

Does this PR introduce a user interface change? If mockups are available, please link/include them here:

Is there a release notes update needed for this change?:

Additional documentation:

[coveralls]

coverage: 97.774%. remained the same
when pulling ee2584e on 319-update-github-actions
into 6bc2261 on develop.

[ekraffmiller]

Closing this to trigger the PR reopen event

[ekraffmiller]

Re-opening to test that github actions will run

[g-saracca]

Looks good to me

[GPortas]

Looks good.