Next fixes, iteration #2

[alekseykulikov]

Prev: #34 Tasks:

• [x] add .yaml config support #23
• [x] remove logLevel in favor of a default action behavior: notify only when attention needed (from unix: when system has nothing to say, it should say nothing)
• [x] use https://github.com/actions/toolkit/tree/master/packages/artifact to upload artifacts automatically
• [x] send slack notification
• [x] rename applicationGithubToken to githubCheck -> report only about errors, link to results, fix pluralization, skip when no token or githubCheck: false
• [x] add support for problem matchers

Next:

• PR to master (reset node_modules for a clear review)
• docs: readme + recipes
• add examples for netlify integration using community actions #30 #31
• close/comment all issues

Later:

• (collect) parallel & stable results collection with PSI
• (notify) integrate failed checks with action annotations
• (upload, possible) cache results between runs with cache api (docs)
• (upload, possible) gist upload (link to results, rename personalGithubToken, docs about credentials)

[alekseykulikov]

Failed to check assertions against of 1 URL.

2 results for https://treo.sh/ – [[report]()] [[compare]()]

❌ offscreen-images failure for maxLength assertion: defer offscreen images [...]        Expected <= 0, but found 1

⚠️ mainthread-work-breakdown warning for minScore assertion: minimize main-thread work [...]         Expected >=0.9, but found 0.83