Description

If I run docker-compose -p SomethingWithMixedCase, the project name is downcased for most commands, but not docker-compose down.

Steps to reproduce the issue:

1. Create docker-compose.yml with any valid compose file, e.g.

   services: hello-world: image: hello-world

2. Create the resources with up or run using a project name with mixed case, e.g.

   $ docker-compose -p HelloWorld run hello-world [+] Running 1/1  ⠿ Network helloworld_default Create... 0.1s

   Note that it downcases the project name.

3. Attempt to remove the resources with down using the same project name, e.g.

   $ docker-compose -p HelloWorld down

Describe the results you received:

[+] Running 1/0 ⠿ HelloWorld Warning: No resource found to remove 

Describe the results you expected:

[+] Running 2/2 ⠿ Container helloworld_hello-world_1 Removed 0.1s ⠿ Network helloworld_default Removed 0.1s 

Additional information you deem important (e.g. issue happens only occasionally):

This works as expected in docker-compose 1.x.

Output of docker-compose --version:

Docker Compose version v2.0.0-rc.1 

Output of docker version:

Client: Cloud integration: 1.0.17 Version: 20.10.8 API version: 1.41 Go version: go1.16.6 Git commit: 3967b7d Built: Fri Jul 30 19:55:20 2021 OS/Arch: darwin/amd64 Context: default Experimental: true Server: Docker Engine - Community Engine: Version: 20.10.8 API version: 1.41 (minimum version 1.12) Go version: go1.16.6 Git commit: 75249d8 Built: Fri Jul 30 19:52:10 2021 OS/Arch: linux/amd64 Experimental: false containerd: Version: 1.4.9 GitCommit: e25210fe30a0a703442421b0f60afac609f950a3 runc: Version: 1.0.1 GitCommit: v1.0.1-0-g4144b63 docker-init: Version: 0.19.0 GitCommit: de40ad0