2021.08.0

WARNING: this Dockerfile now only works with YYYY.MM.PATCH (this is because directories used to be structured in three parts like 1.9.0 and are now in two like 2021.08)

1.9.0.1

BREAKING: change how python is installed, some of the PATH definitions, etc.
- also bump python version from 3.6.5 to 3.8.10 and 3.9.5 (for consistency with other products)
Add R 4.1.0 to the Connect image

1.8.8.2

Add NEWS.md