Support tailwind.config.js

[chiefcll]

Upgrading recommends naming the config file tailwind.config.js.

https://tailwindcss.com/docs/upgrading-to-v1/#3-rename-tailwind-js-to-tailwind-config-js

Please support either names. Thanks

[chiefcll]

VS code just started working for me with it named tailwind.config.js. Not sure if this is an issue. I just see it only looking for the other file:

vscode-tailwindcss/src/extension.js

Line 23 in 850826c

const fileSystemWatcher = workspace.createFileSystemWatcher('**/tailwind.js')