Replace codecov with their GHA thing

[A5rocks]

Fixes #2650

I'm not sure this works. We'll see!

[A5rocks]

Oh this is gonna wreck builds.sr.ht things. I don't think they work, anyways?

[codecov]

Codecov Report

Merging #2653 (5aabe95) into master (b21d4b9) will increase coverage by 5.93%.
The diff coverage is n/a.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2653      +/-   ##
==========================================
+ Coverage   91.73%   97.67%   +5.93%     
==========================================
  Files         118      124       +6     
  Lines       16444    16731     +287     
  Branches     2970        0    -2970     
==========================================
+ Hits        15085    16342    +1257     
+ Misses       1244      389     -855     
+ Partials      115        0     -115     

see 54 files with indirect coverage changes

[A5rocks]

Quick note to self, if this works then:

• remove JOB_NAME cruft
• remove the old copying-over-coveragerc hack

[A5rocks]

See https://app.codecov.io/gh/python-trio/trio/pull/2653

Looks like it works.

[webknjaz]

See https://app.codecov.io/gh/python-trio/trio/pull/2653

Looks like it works.

It's 3 uploads short it seems..

Coverage data is based on HEAD ca40b5e
(28 uploads)
compared to BASE b21d4b9
(25 uploads)

Commits have different number of coverage report uploads learn more

[A5rocks]

I can certainly see why we had the name, previously. Let me add that back, quickly.

[webknjaz]

It's 3 uploads short it seems..

I wonder if these are those external FreeBSD jobs.

[A5rocks]

Oh wow I panicked too much, looks like this PR (as of last complete snapshot) makes 3 more uploads, not 3 less. Weird, but I'll take it!