Please follow the official GitHub docs here and use @vercel/ncc to compile the action into one dist/index.js file. Do not commmit node_modules directory as it contains loads of files.

• install vercel with npm install -g @vercel/ncc
• create src/index.js and action.yml files
• run npm install
• run ncc build src/index.js
• commit src/index.js, dist/index.js and action.yml