I had this same issue and solved it by installing node in my Dockerfile for the builder step, and installing the packages right before the call to RUN mix assets.deploy:
RUN npm install --prefix assets/
It took me a while to figure this out since while I was getting the same error message of Error: Cannot find module 'tailwindcss/plugin', the package that I was actually missing was flowbite (that’s on me, I had added this package but had forgotten about it).
