Update parso to 0.2.1

[DonJayamanne]

Fixes #1833
Fixes #1721

@brettcannon If updating Parso fixes #1721, should't we consider including this into the next release (delaying the release) or releasing a patch asap?
VS Code seems to plan releasing the Outline feature in the next version. If they do, then we'll have a larger (if not all) users facing the same issue of intellisense not working due to the outline feature.

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[codecov]

Codecov Report

Merging #1841 into master will decrease coverage by 0.03%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1841      +/-   ##
==========================================
- Coverage    74.3%   74.27%   -0.04%     
==========================================
  Files         282      282              
  Lines       13191    13191              
  Branches     2371     2371              
==========================================
- Hits         9801     9797       -4     
- Misses       3259     3263       +4     
  Partials      131      131

Impacted Files	Coverage Δ
...reter/locators/services/cacheableLocatorService.ts	91.83% <0%> (-4.09%)	⬇️
src/client/debugger/mainV2.ts	77.91% <0%> (-0.81%)	⬇️
...rc/client/debugger/PythonProcessCallbackHandler.ts	53.61% <0%> (-0.66%)	⬇️
src/client/debugger/Main.ts	52.34% <0%> (+0.49%)	⬆️

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[derekwallace]

@DonJayamanne Updating parso to 0.2.1 does not fix #1721. It does prevent some error messages in the developer console.