Update Release branch for August Release (#13401)

* update version number and npm install to update package-lock.json

* update changelog version and date

* update news for changelog.md

* update generated TPN

Co-authored-by: Ian Huff <ianhuff@ravikun-dev2.redmond.corp.microsoft.com>

Author: IanMatthewHuff

CHANGELOG.md

@@ -1,9 +1,12 @@
 # Changelog
 
-## 2020.8.0-rc (5 August 2020)
+## 2020.8.0 (12 August 2020)
 
 ### Enhancements
 
+1. Cell id and cell metadata are now passed as the metadata field for execute_request messages.
+   (thanks [stisa](https://github.com/stisa/))
+   ([#13252](https://github.com/Microsoft/vscode-python/issues/13252))
 1. Add "Restart Language Server" command.
    ([#3073](https://github.com/Microsoft/vscode-python/issues/3073))
 1. Support multiple and per file interactive windows. See the description for the new 'python.dataScience.interactiveWindowMode' setting.