Upgrade lerna to current beta. - #5300

* Add new flow preset (#5288)

* Fix PathHoister hoisting JSX member expressions on "this". (#5143)

The PathHoister ignored member references on "this", causing it
to potentially hoist an expression above its function scope.

This patch tells the hoister to watch for "this", and if seen,
mark the nearest non-arrow function scope as the upper limit
for hoistng.

This fixes #4397 and is an alternative to #4787.

* Fix PathHoister hoisting before bindings. (#5153)

Fixes #5149 and enables a few additional safe hoists.

* Fix linting error

* feature: Support pure expressions in transform-react-constant-elements (#4812)

* Fix loose for-of with label (#5298)

* Rewrite Hub as interface #5047 (#5050)

* Rewrite Hub as interface #5047

* Update index.js

* Avoid adding unnecessary closure for block scoping (#5246)

When you write

```
for (const x of l) {
  setTimeout(() => x);
}
```

we need to add a closure because the variable is meant to be block-scoped and recreated each time the block runs. We do this.

However, we also add the closure when no loop is present. This isn't necessary, because if no loop is present then each piece of code runs at most once. I changed the transform to only add a closure if a variable is referenced from within a loop.

* Add greenkeeperio-bot to mention-bot blacklist (#5301) [skip ci]

* Upgrade lerna to current beta. (#5300)

* Revert "Upgrade lerna to current beta." (#5303)

* Add charset so tests work with convert-source-map@>1.4 (#5302)

* Add CHANGELOG for 6.23.0 [skip ci] (#5304)

* Update babel-types README from script.

* v6.23.0

* Revert change that lerna force-committed.

* Revert "Rewrite Hub as interface #5047" (#5306)

* v6.23.1

* Revert lerna again