@types/koa: new http2/node 9 dependency is a breaking change without major version number update

• [ x] I tried using the @types/koa package and had problems.
• [x ] I tried using the latest stable version of tsc. https://www.npmjs.com/package/typescript
• I have a question that is inappropriate for StackOverflow. (Please ask any appropriate questions there).
• [ x] Mention the authors (see Definitions by: in index.d.ts) so they can respond.
  • Authors: @DavidCai1993 @jkeylu @brikou

The dependencies for @types/koa 2.0.45 have changed in a breaking way from version 2.0.44 (it now must be compiled using node 9) but there's been no change to the major version number. This violates semver and breaks people's builds. I'm not making a PR because this seems like an administrative issue rather than technical. Am I missing something?

I'm also seeing this error, which I guess to be related: node_modules/@types/koa/index.d.ts(104,14): error TS2694: Namespace '"url"' has no exported member 'URL'.

Thanks!

Start by comparing the @types/koa 2.0.44 and 2.0.45 dependency metadata and reviewing node_modules/@types/koa/index.d.ts around line 104. Reproduce the reported URL type error with the stated TypeScript setup, then determine the appropriate compatibility or versioning change and verify that the affected build succeeds.