[#238] Add codecov to pr creation

[pnatashap]

• Add codecov check to PR creation
• Change url in codecov
• Threshold is 90 (real is more then 96)

Fix https://github.com/cqfn/pdd/issues/238

[pnatashap]

@yegor256 please take a look

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (63948d2) 95.50% compared to head (8db7aaa) 95.50%. Report is 47 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #240 +/- ## ======================================= Coverage 95.50% 95.50% ======================================= Files 10 10 Lines 356 356 ======================================= Hits 340 340 Misses 16 16 ```

:umbrella: View full report in Codecov by Sentry.
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[yegor256]

@rultor merge

[rultor]

@rultor merge

@yegor256 OK, I'll try to merge now. You can check the progress of the merge here

[rultor]

@rultor merge

@yegor256 Done! FYI, the full log is here (took me 5min)