Dev Containers: set GIT_ASKPASS to use GitHub auth token

• VSCode Version: 1.81.1 6c3e3dba23e8fadc360aed75ce363ba185c49794 x64 (installed via rpm-ostree)

• Local OS Version: Fedora Linux 38.20230826.0 (Silverblue) x86_64

• Remote Extension/Connection Type: Containers

• Logs:
  With credentials entered when prompted:

[1240 ms] Dev Containers 0.304.0 in VS Code 1.81.1 (6c3e3dba23e8fadc360aed75ce363ba185c49794).
[1240 ms] Start: Run: docker version --format {{.Server.APIVersion}}
[1260 ms] 1.43
[8925 ms] Start: Run: git ls-remote https://github.com/frenetisch-applaudierend/konoma-time.git
[20777 ms] 
[20778 ms] remote: Support for password authentication was removed on August 13, 2021.
remote: Please see https://docs.github.com/en/get-started/getting-started-with-git/about-remote-repositories#cloning-with-https-urls for information on currently recommended modes of authentication.
fatal: Authentication failed for 'https://github.com/frenetisch-applaudierend/konoma-time.git/'

[20778 ms] Exit code 128

Without credentials entered when prompted:

[852 ms] Dev Containers 0.304.0 in VS Code 1.81.1 (6c3e3dba23e8fadc360aed75ce363ba185c49794).
[851 ms] Start: Run: docker version --format {{.Server.APIVersion}}
[891 ms] 1.43
[5615 ms] Start: Run: git ls-remote https://github.com/frenetisch-applaudierend/konoma-time.git
[7007 ms] 
[7007 ms] remote: Repository not found.
fatal: Authentication failed for 'https://github.com/frenetisch-applaudierend/konoma-time.git/'

[7008 ms] Exit code 128

Steps to Reproduce:

1. In command palette run "Dev Containers: Clone Repository in Container Volume..."
2. Select a private repository
3. Select branch
4. I get asked for my github username and password. If I provide anything (including a personal access token), I get the error message: "Cannot access the repository 'https://github.com/frenetisch-applaudierend/konoma-time.git'." In the Dev Container terminal I see the attached log output, with the error being "remote: Support for password authentication was removed on August 13, 2021."
   If I do not enter any credentials (i.e. blank username/password) the error message in the console is simply "Authentication failed for 'https://github.com/frenetisch-applaudierend/konoma-time.git'"

Does this issue occur when you try this locally?: No (I can clone using the "Git: Clone" command)
Does this issue occur when you try this locally and all extensions are disabled?: N/A

I found it interesting that the repository is found in step 2) indicating that this part uses the github credentials obtained via Oauth by the Github Extension, but to clone then tries to obtain username/password.