Tweak codecov settings

[blink1073]

• Turn off the github annotations
• Require 50% of new code to be covered (we can still override and merge)
• Show green coverage at 80%
• Wait until most builds have finished before posting the comment
• Wait until all the other builds finish before assigning status

[codecov]

Codecov Report

Base: 80.03% // Head: 80.01% // Decreases project coverage by -0.01% ⚠️

Coverage data is based on head (93d1dbd) compared to base (53380a7).
Patch has no changes to coverable lines.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1113      +/-   ##
==========================================
- Coverage   80.03%   80.01%   -0.02%     
==========================================
  Files          68       68              
  Lines        8013     8013              
  Branches     1586     1586              
==========================================
- Hits         6413     6412       -1     
  Misses       1179     1179              
- Partials      421      422       +1     

Impacted Files	Coverage Δ
jupyter_server/serverapp.py	80.03% <0.00%> (-0.09%)	⬇️

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report at Codecov.
📢 Do you have feedback about the report comment? Let us know in this issue.