Remove tools/code_check and update codecov

[chapulina]

See gazebo-tooling/action-gz-ci#32 and gazebo-tooling/release-tools#446

[codecov]

Codecov Report

Merging #219 (0a11399) into ign-common3 (8f3b267) will increase coverage by 1.38%.
The diff coverage is 70.87%.

❗ Current head 0a11399 differs from pull request most recent head a45a6c3. Consider uploading reports for the commit a45a6c3 to get more accurate results

@@               Coverage Diff               @@
##           ign-common3     #219      +/-   ##
===============================================
+ Coverage        73.80%   75.18%   +1.38%     
===============================================
  Files               68       73       +5     
  Lines             9261    10326    +1065     
===============================================
+ Hits              6835     7764     +929     
- Misses            2426     2562     +136     

Impacted Files	Coverage Δ
av/include/ignition/common/ffmpeg_inc.hh	0.00% <0.00%> (ø)
graphics/src/SVGLoader.cc	86.83% <ø> (ø)
include/ignition/common/Filesystem.hh	100.00% <ø> (ø)
include/ignition/common/Util.hh	100.00% <ø> (ø)
av/src/HWEncoder.cc	20.00% <20.00%> (ø)
graphics/src/SkeletonAnimation.cc	40.00% <35.71%> (-5.34%)	⬇️
graphics/src/Skeleton.cc	42.47% <44.44%> (-0.25%)	⬇️
graphics/src/Image.cc	67.08% <52.72%> (+6.97%)	⬆️
src/Filesystem.cc	76.11% <58.13%> (-3.33%)	⬇️
av/src/VideoEncoder.cc	76.25% <79.86%> (+27.92%)	⬆️
... and 37 more

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