…-merge-0.19

Merge `branch-0.19` into `branch-21.06` [skip ci]

This PR updates the `0.20` references in `CHANGELOG.md` to be `21.06`.

Authors:
  - AJ Schmidt (https://github.com/ajschmidt8)

Approvers:
  - https://github.com/jakirkham
  - Dillon Cullinan (https://github.com/dillon-cullinan)

URL: #781

…rs (#784)

When multiple projects included via CPM depend on RMM we need
to make sure that we only try to add target `thrust_internal`.

Authors:
  - Robert Maynard (https://github.com/robertmaynard)

Approvers:
  - Keith Kraus (https://github.com/kkraus14)

URL: #784

The new version includes `fmt` version 7.1.3 which fixed the problem with cuda 10.x.

@harrism @kkraus14

Authors:
  - Rong Ou (https://github.com/rongou)

Approvers:
  - Keith Kraus (https://github.com/kkraus14)
  - Mark Harris (https://github.com/harrism)
  - Mike Wendt (https://github.com/mike-wendt)
  - AJ Schmidt (https://github.com/ajschmidt8)

URL: #658

This PR updates the environment variable thats used to determine the `cuda_version` varaible in our conda recipes.

The `CUDA` environment variable is explicitly set by the Ops team in our Jenkins jobs, whereas `CUDA_VERSION` comes from the `nvidia/cuda` Docker images that we base our images from.

Authors:
  - AJ Schmidt (https://github.com/ajschmidt8)

Approvers:
  - Ray Douglass (https://github.com/raydouglass)

URL: #785