Support for credentials from environment variables

[vova-lantsov-dev]

Describe the solution you'd like
For CI/CD purposes, it'd be really useful to be able to auth via environment variables that contains the Docker config data. Here is an example: https://docs.gitlab.com/ee/ci/docker/using_docker_images.html#determine-your-docker_auth_config-data

Something like that:

[HofmeisterAn]

The env variable DOCKER_AUTH_CONFIG is not yet supported. Base64 just works with ~/.docker/config.json. Anyway, it is not difficult to implement. We just need another provider. Something like:

testcontainers-dotnet/src/Testcontainers/Builders/Base64Provider.cs

Line 12 in 0f4d0ff

internal sealed class Base64Provider : IDockerRegistryAuthenticationProvider

To read the value from the env variable or ~/.testcontainers.properties file, we need another getter in:

testcontainers-dotnet/src/Testcontainers/Configurations/PropertiesFileConfiguration.cs

Line 11 in 0f4d0ff

internal sealed class PropertiesFileConfiguration : CustomConfiguration, ICustomConfiguration

Probably we can use the same test cases, like we are using for ~/.docker/config.json:

testcontainers-dotnet/tests/Testcontainers.Tests/Unit/Configurations/DockerRegistryAuthenticationProviderTest.cs

Line 62 in 0f4d0ff

public sealed class Base64ProviderTest

Would you like to create a pull request?

[vova-lantsov-dev]

Sure, I would try