Add @babel/plugin-proposal-dynamic-import to @babel/preset-env

[nicolo-ribaudo]

Q	A
Fixed Issues?	Closes babel/babel-loader#515, closes #9057 (by @thiagoarrais), ref babel/babel-loader#714
Patch: Bug Fix?
Major: Breaking Change?
Minor: New Feature?
Tests Added + Pass?	Yes
Documentation PR Link
Any Dependency Changes?
License	MIT

Follow up to #9552: that PR cretes the new plugin; this PR adds it to @babel/preset-env.

I'm really thankful that @loganfsmyth added the supportsDynamicImport flag to babel-loader and rollup-plugin-babel a long time ago 🙂

cc @Andarist Is this ok for rollup-plugin-babel?

[babel-bot]

Build successful! You can test your changes in the REPL here: https://babeljs.io/repl/build/11012/

[babel-bot]

Build successful! You can test your changes in the REPL here: https://babeljs.io/repl/build/10977/

[Andarist]

Well - I guess it’s hard to tell if this can break somebody’s expectations, considering in how many ways babel configs may be written. But I wouldn’t stop this because of that because i think possibility of breakage is low.

[nicolo-ribaudo]

I think that this could only break only if someone disables the modules transform plugin using excludes instead of modules: false (I don't know if it is actually possible?)

[nicolo-ribaudo]

Merged as ef3f555

[klimashkin]

Why do we show Dynamic import can only be supported when transforming ES modules to AMD, CommonJS or SystemJS. Only the parser plugin will be enabled warning in case of umd target even if there is no import() in the code?