Allow webpack 5 as peer dependency

[jorrit]

This PR contains:

• bugfix
• feature
• refactor
• documentation
• other

Are tests included?

• yes (bugfixes and features will not be merged without tests)
• no

Breaking Changes?

• yes (breaking changes will not be merged unless absolutely necessary)
• no

List any relevant issue numbers: #270

[codecov-commenter]

Codecov Report

Merging #271 (86dbfe6) into master (1b9142e) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##            master      #271   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            3         3           
  Lines          122       122           
=========================================
  Hits           122       122           

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[jorrit]

This PR was reverted by 830a1b2.

[shellscape]

It actually wasn't. It was reverted by the previous commit, and reinstated by the commit you referenced.

[jorrit]

Sorry, I shouldn't have commented before the third coffee in the morning. My apologies.