Plugin does not re-compile in Rollup watch mode

[matthew-dean]

I thought maybe this was a Less issue, but I did some debugging, and in my Rollup config, I have a TypeScript compiler and a Less compiler.

In Rollup watch mode, I can trace and see that @rollup/plugin-typescript fires its plugin methods and re-compiles TypeScript. However, for this plugin, the rollup-plugin-less transform method never fires again, and Rollup will always provide the same (initial) compiled CSS bundle.