Fix postcss plugin options

[o-alquimista]

Description

The current configuration doesn't work. If you check the output, the vendor prefixes aren't there.

I had to change the syntax a bit. It's a tiny fix.

You can see an example of the correct syntax here and here.

Type of changes

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

Checklist

• I have read the contributing guidelines
• My code follows the code style of the project (using npm run lint)
• My change introduces changes to the documentation
• I have updated the documentation accordingly
• I have added tests to cover my changes
• All new and existing tests passed

Related issues

[XhmikosR]

What doesn't work? Because I do see the prefixes added in our dist files.

[o-alquimista]

What doesn't work? Because I do see the prefixes added in our dist files.

This section is for users wishing to integrate Bootstrap in their Webpack configuration. It's not used to generate Bootstrap dist files.

[XhmikosR]

So, you are saying this here https://github.com/twbs/examples/tree/main/webpack doesn't include the prefixes, right?

If so please make a PR against the examples repo first.

[XhmikosR]

On a side note, I probably mixed up the syntax in twbs/examples@a242d6f

[o-alquimista]

So, you are saying this here https://github.com/twbs/examples/tree/main/webpack doesn't include the prefixes, right?

If so please make a PR against the examples repo first.

Yes. It's done.

[julien-deramond]

LGTM based on twbs/examples#297 (review) (verified in twbs/examples repo)