fix: env vars with hyphens are not processed properly

[shazron]

old regex: https://regex101.com/r/sBfXak/1
new regex: https://regex101.com/r/dOa3sT/1

Closes #139

• Replaced \w+ with [a-zA-Z0-9_-]+ (\w is equivalent to [a-zA-Z0-9_])
• This can be [\w-]+ as well, but I wanted to be explicit.

How Has This Been Tested?

• npm test

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• I have signed the Adobe Open Source CLA.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[codecov]

Codecov Report

Merging #140 (69cf07c) into master (592171f) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master      #140   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           11        11           
  Lines         1320      1320           
  Branches       351       351           
=========================================
  Hits          1320      1320           

Impacted Files	Coverage Δ
src/utils.js	100.00% <100.00%> (ø)

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[sandeep-paliwal]

LGTM