fix: do not crash with data URLs

[alexander-akait]

This PR contains a:

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

Motivation / Use-Case

fixes #1141

Breaking Changes

No

Additional Info

No

[codecov]

Codecov Report

Merging #1142 into master will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #1142   +/-   ##
=======================================
  Coverage   99.18%   99.18%           
=======================================
  Files          10       10           
  Lines         612      612           
  Branches      188      189    +1     
=======================================
  Hits          607      607           
  Misses          5        5           

Impacted Files	Coverage Δ
src/plugins/postcss-url-parser.js	100.00% <100.00%> (ø)
src/utils.js	97.98% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update bc7b18d...7a19b6a. Read the comment docs.