Specify sass-loader major version in example

[zgoda]

v11 is not compatible with webpack v4

What kind of change does this PR introduce?

Documentation change

Did you add tests for your changes?

Summary

sass-loader@11 is not compatible with webpack@4

Does this PR introduce a breaking change?

no

Other information

Please paste the results of preact info here.

$ LANGUAGE=C preact info

Command 'preact' not found, did you mean:

  command 'precat' from deb aspell (0.60.8-1build1)

Try: sudo apt install <deb name>

[changeset-bot]

⚠️ No Changeset found

Latest commit: 6333964

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

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[rschristian]

@zgoda preact info will only work if you have Preact-CLI installed as a global dependency. If you've used NPX to use the CLI, run npx preact-cli info.