fix: wrap pip/conda pkgs in single quotes

[kaczmarj]

This changes the installation of conda and pip packages from

conda install traits>=4

to

conda install 'traits>=4'

This prevents writing to a file named =4.

[codecov-io]

Codecov Report

Merging #239 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #239   +/-   ##
=======================================
  Coverage   80.95%   80.95%           
=======================================
  Files          33       33           
  Lines        1512     1512           
  Branches      156      156           
=======================================
  Hits         1224     1224           
  Misses        213      213           
  Partials       75       75

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