Add Acceptance Criteria for Visual Changes to PR Template

[acouch]

Is your feature request related to a problem? Please describe.
We don't have a documented AC for visual changes.

Describe the solution you'd like
Add AC for visual changes to PR template.

This should include the breakpoints we want to focus on for now.

Longer term we may add an end to end test like Cypress, visual regression tests, pa11y or other tests.

[thekaveman]

cc @srhhnry @machikoyasuda @mrose914 @vykster

Especially as @srhhnry and @machikoyasuda work to research standards around State/Fed design systems and guidelines, including breakpoints. Much work documented/happening in cal-itp/benefits#583 and cal-itp/services-team#6.

We should be in alignment across all Cal-ITP web properties.

[acouch]

@thekaveman Thanks for the resources. Agreed it would be ideal to have a standard of tools and practices across the projects. Will work to align any time we have the opportunity. If there is anything specific here let me know.