Extending jsonreport.py to also include all branch attributes

[SZVector]

The current jsonreport does not include the attributes for covered_branches and missing_branches.

This PR extends jsonreport.py such that it includes these attributes; it also updates test_json.py to account for these newly-dumped attributes.

Current test status:

  py27: commands succeeded
SKIPPED:  py35: InterpreterNotFound: python3.5
  py36: commands succeeded
SKIPPED:  py37: InterpreterNotFound: python3.7
SKIPPED:  py38: InterpreterNotFound: python3.8
SKIPPED:  py39: InterpreterNotFound: python3.9
SKIPPED:  pypy2: InterpreterNotFound: pypy2
SKIPPED:  pypy3: InterpreterNotFound: pypy3

[aytey]

@nedbat any thoughts on this? This seems like a great change, as it allows us to get access to data that would otherwise be missing from the json report.

[codecov-io]

Codecov Report

Merging #966 into master will not change coverage by %.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #966   +/-   ##
=======================================
  Coverage   94.10%   94.10%           
=======================================
  Files          86       86           
  Lines       12107    12107           
  Branches     1212     1212           
=======================================
  Hits        11393    11393           
  Misses        580      580           
  Partials      134      134           

Impacted Files	Coverage Δ
coverage/jsonreport.py	100.00% <ø> (ø)
tests/test_json.py	100.00% <ø> (ø)

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[nedbat]

Thanks, I'll add the fields to the individual files also.

[nedbat]

This is available in 5.1: https://pypi.org/project/coverage/5.1/