Send correct conda activation command in windows gitbash

[joelcthomas]

For #3810

• Pull request represents a single change (i.e. not fixing disparate/unrelated things in a single PR)
• Title summarizes what is changing
• Has a news entry file (remember to thank yourself!)
• Unit tests & system/integration tests are added/updated
• Test plan is updated as appropriate
• package-lock.json has been regenerated by running npm install (if dependencies have changed)

[codecov]

Codecov Report

Merging #3917 into master will decrease coverage by 1%.
The diff coverage is 50%.

@@           Coverage Diff           @@
##           master   #3917    +/-   ##
=======================================
- Coverage      81%     81%   -<1%     
=======================================
  Files         401     401            
  Lines       18516   18522     +6     
  Branches     2975    2977     +2     
=======================================
- Hits        14978   14950    -28     
- Misses       3535    3569    +34     
  Partials        3       3

Flag	Coverage Δ
#Linux	68% <0%> (+1%)	⬆️
#Windows	68% <0%> (+1%)	⬆️
#macOS	68% <0%> (ø)	⬇️

Impacted Files	Coverage Δ
...mentActivationProviders/condaActivationProvider.ts	71% <50%> (-2%)	⬇️
...rc/client/common/errors/moduleNotInstalledError.ts	34% <0%> (-66%)	⬇️
src/client/linters/errorHandlers/standard.ts	40% <0%> (-60%)	⬇️
...c/client/linters/errorHandlers/baseErrorHandler.ts	78% <0%> (-22%)	⬇️
src/client/linters/errorHandlers/errorHandler.ts	78% <0%> (-22%)	⬇️
src/client/linters/errorHandlers/notInstalled.ts	45% <0%> (-16%)	⬇️
src/client/linters/baseLinter.ts	93% <0%> (-6%)	⬇️
src/client/common/process/pythonProcess.ts	95% <0%> (-3%)	⬇️
src/client/interpreter/helpers.ts	84% <0%> (-2%)	⬇️
src/client/common/platform/fileSystem.ts	66% <0%> (ø)	⬇️
... and 1 more

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[DonJayamanne]

@joelcthomas
With the latest changes to the extension, I do not believe this is necessary any more.
Please could you download the latest development version of the extension and test this out.

[joelcthomas]

@DonJayamanne
I confirm it works as expected with new conda activate instead of source activate in the latest dev version.