Replace simplejson with json

[christian-monch]

Fixes issue #181

This PR replaces simplejson with json. Merging this should stop the import error that will be introduced with the datalad PR #7014 (datalad/datalad#7014) is released, because PR #7014 will remove simplejson from the requirements and datalad-container would stop working.

Merging this will also fix the datalad-container extension test error in PR #7014

[codeclimate]

Code Climate has analyzed commit 535b38d and detected 0 issues on this pull request.

View more on Code Climate.

[yarikoptic]

thank you! I have restarted appveyor which freaked out.

[codecov]

Codecov Report

Base: 93.96% // Head: 93.96% // No change to project coverage 👍

Coverage data is based on head (535b38d) compared to base (0efcbba).
Patch coverage: 33.33% of modified lines in pull request are covered.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #182   +/-   ##
=======================================
  Coverage   93.96%   93.96%           
=======================================
  Files          19       19           
  Lines         878      878           
=======================================
  Hits          825      825           
  Misses         53       53           

Impacted Files	Coverage Δ
datalad_container/containers_run.py	87.03% <0.00%> (ø)
datalad_container/containers_add.py	91.60% <66.66%> (ø)

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.

[christian-monch]

thank you! I have restarted appveyor which freaked out.

Thx!

[christian-monch]

@yarikoptic: shall we merge this?

[yarikoptic]

sure, let's do it!