ES2020 lib required because of @types/es-abstract

[buschtoens]

With 9342da7 I updated the intl library related dependencies to the latest version. This resolved the issue with the divergent TranslationAST / MessageFormat types.

However @types/es-abstract, which is a dependency of @formatjs/intl-numberformat assumes methods only added in ES2020, like String#matchAll(). For host projects that do not yet target ES2020 or do not have ES2020 listed in their lib, this will throw type errors.

The fix is trivial: Just raise the compilerOptions.target to ES2020 or add ES2020 to compilerOptions.lib.

Is this something we should document somewhere?

[longlho]

An addition to this to always add ["esnext.intl", "es2017.intl", "es2018.intl"] as well