[v3.0] use compiler target ES2020

[dnalborczyk]

This PR contains:

• bugfix
• feature
• refactor
• documentation
• other

Are tests included?

• yes (bugfixes and features will not be merged without tests)
• no

Breaking Changes?

• yes (breaking changes will not be merged unless absolutely necessary)
• no

List any relevant issue numbers:

Description

https://github.com/microsoft/TypeScript/wiki/Node-Target-Mapping

Transpiled code should get smaller (nullish coalescing, optional chaining) and run at native speed.

[codecov]

Codecov Report

Merging #4651 (d063226) into release-3.0.0 (5812006) will increase coverage by 0.07%.
The diff coverage is n/a.

@@                Coverage Diff                @@
##           release-3.0.0    #4651      +/-   ##
=================================================
+ Coverage          98.97%   99.04%   +0.07%     
=================================================
  Files                213      213              
  Lines               7481     7472       -9     
  Branches            2112     2066      -46     
=================================================
- Hits                7404     7401       -3     
  Misses                23       23              
+ Partials              54       48       -6     

Impacted Files	Coverage Δ
src/ast/nodes/VariableDeclaration.ts	97.97% <0.00%> (-0.03%)	⬇️
src/Chunk.ts	100.00% <0.00%> (ø)
src/ast/nodes/ForStatement.ts	100.00% <0.00%> (ø)
src/ast/nodes/MetaProperty.ts	100.00% <0.00%> (ø)
src/ast/nodes/shared/ClassNode.ts	100.00% <0.00%> (ø)
src/ast/nodes/Identifier.ts	100.00% <0.00%> (+1.29%)	⬆️
src/ast/variables/LocalVariable.ts	95.94% <0.00%> (+2.70%)	⬆️
src/ast/nodes/shared/MethodTypes.ts	96.15% <0.00%> (+3.29%)	⬆️
src/ast/nodes/TryStatement.ts	100.00% <0.00%> (+4.54%)	⬆️
cli/logging.ts	94.73% <0.00%> (+5.26%)	⬆️

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[lukastaegert]

According to https://node.green, we are still missing spread operators after optional chaining for this setting.

[dnalborczyk]

interestingly what you are pointing to was a bug in V8 which was fixed in a later iteration: microsoft/TypeScript#46325 if you find yourself or a contributor using that syntax (which is probably fairly unlikely) you could still switch back to ES2019 😉

[lukastaegert]

I guess considering our stellar E2E test coverage and the fact that CI runs the tests at the exact earliest version we promise to support, it is probably safe to go for ES2020

[rollup-bot]

This PR has been released as part of rollup@3.0.0-8. Note that this is a pre-release, so to test it, you need to install Rollup via npm install rollup@3.0.0-8 or npm install rollup@beta. It will likely become part of a regular release later.

[rollup-bot]

This PR has been released as part of rollup@3.0.0. You can test it via npm install rollup.