Since dotnet/sdk:8.0, dotnet restore takes too long on gitlab ci with docker

Challenge: Since dotnet/sdk:8.0, dotnet restore takes too long on GitLab CI with Docker.

Solution: NuGet team has proposed a workaround for this issue:
https://github.com/NuGet/Home/issues/13062

Workaround Steps:

1. Create a file named NuGet.config in the root folder of your project.
2. Add the following content to the file:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <config>
    <add key="globalPackagesFolder" value="NuGetPackages" />
  </config>
</configuration>

3. Commit the changes to your source control.
4. Update your GitLab CI config to use the new NuGet.config file.

Example:

image: mcr.microsoft.com/dotnet/sdk:8.0

stages:
  - restore
  - build

restore:
  stage: restore
  script:
    - dotnet restore --configfile NuGet.config

build:
  stage: build
  script:
    - dotnet build

Additional Information:

• This workaround is not a permanent fix, and it may not work for all projects.
• The NuGet team is working on a permanent fix for this issue.
• In the meantime, you can use this workaround to reduce the time it takes for dotnet restore on GitLab CI with Docker.