esm bundle version (update from 9.0.2 to 9.1.2)

[viT-1]

Is your feature request related to a problem? Please describe.
After updating from 9.0.2 version to 9.1.2 we loss complete codefile lib/vue-property-decorator.js

Describe the solution you'd like
I like vue & vuex solution: they provided dist folder with single esm.min.js, also they publish same files on jsdelivr

Describe alternatives you've considered
Still using v9.0.2 and bundling it to SystemJS version manually as I do.

Additional context
You can see how I use your project for SystemJS bundling.

[tobiasdiez]

An es module build (*.mjs file) would indeed be handy, especially for nuxt bridge / 3 which uses esbuild (maybe refs #403).