Change TypeScript target to es2019

[mpsq]

This library is currently targeting es2020 (see tsconfig.json). This results is narrower compatibility, for example this library is affected by cypress-io/cypress#20753 (because of es2019 does not support optional chaining. Changing the target to es2019 would increase compatibility without affecting too much the output.
What do you think?

[perry-mitchell]

Yes I'd happily accept such a change. Would you be willing to make a PR?

[mpsq]

Of course, see #22

[kibertoad]

@mpsq But why? All modern browsers and supported Node versions are compatible with ES2020.
targetting older ES is likely to have perf impact.

[perry-mitchell]

Ok, after checking this it seems like TS doesn't like the 2019 module type:

And having thought about it for a bit, I do concur with @kibertoad that 2020 should be plenty in terms of browser support. If required it could be compiled, again, to an older format if needed in niche environments (ie. not the concern of this project).

Apologies for wasting time here.. let's leave it as is for now.