Remove patch check from master branch

[tiffon]

Which problem is this PR solving?

Currently if a PR that's merged to master has less than 90% coverage the Jaeger UI repo shows up as failing some checks even if the coverage for the project is above 90%.

This PR endeavor to remove the patch check from the master branch.

Short description of the changes

Add a .codecov.yml config file and configure to only apply the patch check to pull requests.

[codecov]

Codecov Report

Merging #415 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #415   +/-   ##
=======================================
  Coverage   91.46%   91.46%           
=======================================
  Files         174      174           
  Lines        3915     3915           
  Branches      897      897           
=======================================
  Hits         3581     3581           
  Misses        296      296           
  Partials       38       38

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[yurishkuro]

Patch check is not required for merge

[tiffon]

@yurishkuro The intent of this PR is to remove it from the overall repo status check, which drives the green checkbox or red x next to the repo name in the header, by limiting the patch check to pull requests.

[yurishkuro]

I still don't follow. Patch == PR, is it not? Or do you mean we're getting this as red on master builds?

[tiffon]

@yurishkuro I believe the patch status check runs on master based on the most recent merge. That's my theory, anyway.

The field only_pulls is from the docs on commit status, which show the default config:

coverage:
  status:
    patch:
      default:
        # basic
        target: auto
        threshold: null
        base: auto 
        # advanced
        branches: null
        if_no_uploads: error
        if_not_found: success
        if_ci_failed: error
        only_pulls: false
        flags: null
        paths: null

It's my assumption that only_pulls will only apply the check to PRs.

[tiffon]

@yurishkuro I'm not so sure it worked. Will verify with the next PR merged. The config might replace the default for project instead of merging with it.