PTFM-13730: expanding the bash path variable

Summary: Expanding the bash path variable, and uplifting the tests accordingly.

Test Plan: Improved the file_load/vars test.

Reviewers: klai

Reviewed By: klai

Differential Revision: https://phabricator.dnanexus.com/D155
Bump concurrent.futures dependency from v2.1.2 to v2.2.0

Also rewrite the monkey-patch for threadpool executor that
incorporates the fix for http://bugs.python.org/issue16284.
Bump requests dependency from v2.3.0 to v2.4.3
Changelog and version updates for v0.125.0