[13] Set file type in get_asset_info function

[jamesmorrison]

Description of the Change

Added: backwards compatible option to set file type; e.g.:

get_asset_info( 'css/file' )
get_asset_info( 'js/file' )
get_asset_info( 'blocks/file' )
get_asset_info( 'file' )

all work. If file type prefix is not specified, original order (JS, then CSS, then Blocks) is used.

Closes #13

How to test the Change

Run composer test; tests are included to ensure the file prefix is used where set.

Step-by-step:

1. In the scaffold, enqueue an asset and use the prefixed path e.g. get_asset_info( 'css/file' )
2. Run the build: npm install; npm run build
3. Confirm the version and dependencies match

Changelog Entry

Added - backwards compatible option to set file type

Credits

Props @jamesmorrison

Checklist:

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly.
• I have added Critical Flows, Test Cases, and/or End-to-End Tests to cover my change.
• All new and existing tests pass.