Enable codecov partial coverage

[danez]

Q	A
Patch: Bug Fix?	n
Major: Breaking Change?	n
Minor: New Feature?	n
Deprecations?
Spec Compliancy?	n
Tests Added/Pass?	n
Fixed Tickets
License	MIT
Doc PR
Dependency Changes

We already upload json format to codecov (which supports partial coverage) and this enables partial support in codecov.

Coverage will most likely drop.

[codecov]

Codecov Report

Merging #5336 into master will decrease coverage by -5.08%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #5336      +/-   ##
==========================================
- Coverage   89.44%   84.36%   -5.08%     
==========================================
  Files         204      204              
  Lines        9949     9616     -333     
  Branches     2689     2688       -1     
==========================================
- Hits         8899     8113     -786     
+ Misses       1050     1014      -36     
- Partials        0      489     +489

Impacted Files	Coverage Δ
packages/babel-core/src/helpers/merge.js	75% <ø> (-25%)	❌
packages/babel-messages/src/index.js	61.53% <ø> (-24.18%)	❌
...ckages/babel-plugin-transform-runtime/src/index.js	75.4% <ø> (-21.32%)	❌
packages/babel-helper-call-delegate/src/index.js	68% <ø> (-20%)	❌
...kages/babel-traverse/src/path/lib/removal-hooks.js	59.25% <ø> (-18.52%)	❌
...es/babel-plugin-transform-strict-mode/src/index.js	83.33% <ø> (-16.67%)	❌
...l-plugin-transform-es2015-modules-umd/src/index.js	82.14% <ø> (-16.08%)	❌
packages/babel-register/src/node.js	76.56% <ø> (-15.63%)	❌
packages/babel-core/src/api/node.js	66.66% <ø> (-15.16%)	❌
...bel-plugin-transform-react-jsx-source/src/index.js	77.77% <ø> (-15.08%)	❌
... and 119 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 07dd2b1...89e947c. Read the comment docs.

[hzoo]

Sounds like a good idea? Did we do this on babylon already?

[danez]

Yes babylon has this already