Default to output native modules. Add outputSystemJS option.

[joeldenning]

This is a breaking change that changes all create-single-spa projects to default to outputting native ES modules.

[ibacher]

As-is this seems correct. For Webpack, don't we also need to ensure "type": "module" is set in package.json?

[joeldenning]

For Webpack, don't we also need to ensure "type": "module" is set in package.json?

My understanding (might be incomplete) is that "type": "module" in the package.json is needed for webpack to know what kinds of source files it is dealing with, not the output format. I tested this change locally and webpack compiled without issue.

[ibacher]

Perfect! Seems that my approvals are meaningless to GitHub, but that's fine with me.

[joeldenning]

Seems that my approvals are meaningless to GitHub, but that's fine with me.

I removed all write access during the permissions re-do a couple weeks ago, which might be why? I'm opening to changing a setting to make the approval checkmark green instead of gray, if it's possible without granting write access