Docker image v2

[ekilmer]

DO NOT MERGE UNTIL #1018 passes

New naming scheme appends -v# to the image name. The tag part is not changed

Removed Docker Hub pushes. Now we use ghcr.io for both images.

Use GCC for cross-compilation on Linux because Ubuntu and vcpkg have better support for cross-compilation when using GCC

[Ninja3047]

small nit

[ekilmer]

Oh wait. Hmmmm

Successfully tagged ghcr.io/lifting-bits/cxx-common/test-ekilmer_version-docker-images-vcpkg-builder-ubuntu-v2:20.04
WARNING! Using -*** the CLI is insecure. Use --password-stdin.
WARNING! Your password will be stored unencrypted in /home/runner/.docker/config.json.
Configure a credential helper to remove this warning. See
https://docs.docker.com/engine/reference/commandline/login/#credentials-store

Login Succeeded
The push refers to repository [ghcr.io/lifting-bits/cxx-common/test-ekilmer_version-docker-images-vcpkg-builder-ubuntu-v2]
81e69031f664: Preparing
847cbbfcd137: Preparing
6f37ca73c74f: Preparing
unauthorized: unauthenticated: User cannot be authenticated with the token provided.
The push refers to repository [ghcr.io/lifting-bits/cxx-common/test-ekilmer_version-docker-images-vcpkg-builder-ubuntu-v2]
81e69031f664: Preparing
847cbbfcd137: Preparing
6f37ca73c74f: Preparing
unauthorized: unauthenticated: User cannot be authenticated with the token provided.
The push refers to repository [ghcr.io/lifting-bits/cxx-common/test-ekilmer_version-docker-images-vcpkg-builder-ubuntu-v2]
81e69031f664: Preparing
847cbbfcd137: Preparing
6f37ca73c74f: Preparing
unauthorized: unauthenticated: User cannot be authenticated with the token provided.
Sending build context to Docker daemon  5.632kB