HD Pipeline package depends on two other packages: PostProcessing and Render-pipelines.core. Fetching HD Pipeline in an empty Unity 3D template successfully downloads dependent packages. This can be seen in Project tab. However, Package Manager UI doesn't reflect the latest changes and only shows the package that the user has clicked on to download.

Steps for reproduction:
1) In Unity hub, create an empty Unity project (select `3D` as template)
2) Open Window > Package Manager
3) Fetch Render-pipelines.high-definition
4) Once Package Manager fetches everything, observe in Project tab that both Render-pipelines.core and Postprocessing packages are also downloaded along with HDRP
5) However, Package Manager UI doesn't update and it doesn't show that Render-pipelines.core and Postprocessing packages are fetched

Notes:
- Not a regression
- Latest tested version is 2018.1.0f1 (21784bcc13fa)