Feat merge options

[cap-Bernardito]

This PR contains a:

• bugfix
• new feature
• code refactor
• test update
• typo fix
• metadata update

Motivation / Use-Case

Merges configuration parameters with passed parameters (passed parameters overwrite the configuration)

Breaking Changes

Сonfig files are loaded by default and combined with passed options.
To reverse this behavior, you must specify config:false

Additional Info

• replace import-cwd package on require;
• allow pass plugins in object format plugins: {'postcss-short': { prefix: 'x' }}
• combines configuration plugins with the passed parameters (if you need to cancel config loading, you must specify config:false)

[codecov]

Codecov Report

Merging #441 into master will increase coverage by 1.53%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #441      +/-   ##
==========================================
+ Coverage   95.67%   97.20%   +1.53%     
==========================================
  Files           6        5       -1     
  Lines         208      179      -29     
  Branches       64       48      -16     
==========================================
- Hits          199      174      -25     
+ Misses          9        5       -4     

Impacted Files	Coverage Δ
src/index.js	97.18% <100.00%> (+4.68%)	⬆️
src/utils.js	96.42% <100.00%> (-0.28%)	⬇️

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