Packages can now augment the ref unwrap bail types in their own `d.ts`.
Also updated the build script to auto concat any files in a package's
`types` directory to the final generated `d.ts`.
- `@vue/reactivity` should no longer require `libs: ["DOM"]` in tsconfig
- Properly bail on `VNode` and `ComponentPublicInstance` in runtime-core
BREAKING CHANGE: Reactivity APIs adjustments:
- `readonly` is now non-tracking if called on plain objects.
`lock` and `unlock` have been removed. A `readonly` proxy can no
longer be directly mutated. However, it can still wrap an already
reactive object and track changes to the source reactive object.
- `isReactive` now only returns true for proxies created by `reactive`,
or a `readonly` proxy that wraps a `reactive` proxy.
- A new utility `isProxy` is introduced, which returns true for both
reactive or readonly proxies.
- `markNonReactive` has been renamed to `markRaw`.