message: Add TS 3.8 breaking feature in CHANGELOG (missed)
diff: # 2.5.1 Feb 22, 2020
  +- **Breaking change** (TypeScript only) The `*.d.ts` files now contain TypeScript 3.8 features, `#private`, which is not usable in older versions
  - Add `isBigInt(value)` to allow `BigInt` checks. Also add support in `bnToBn` as well as number conversion utils
  - Add `isChildClass(Parent, Child?)` to check if a class extends the parent, asserting Child is Parent
  -- (internal) Use `#<varname>` instead of `private _<varname>` for private class variables
  +- (internal) Use `#<field>` instead of `private _<field>` for private class variables
  # 2.4.1 Feb 18, 2020
  