Update main.yml to use node-version v14

[rchutzz]

When trying to run npm run build, the .yml file tries to use node v10.x which is incompatible with some of dependencies like the newer version of tailwindcss

[rchutzz]

I have verified node version v14.x and all the way to v19.7.0 works, but doesn't work with with v20.1.0. if you want to change the main.yml test to a higher version, that would be fine and help when running audit fix to update other dependencies.