testcontainers 1.12.2 and up does not replace versions from .env

Hello,

In a couple of projects we were using test containers version 1.12.1 with local-compose and pull enabled.
I have tried to update to testcontainers 1.12.5 however I have start to some errors on my console.

We are using single file docker-compose.yml version 2 and all image versions inside the compose configuration are coming from .env file
In docker-compose.yml we have mysql image with version placeholder
image: eu-west-1.amazonaws.com/content-delivery/mysql:${mysqlversion}
In .env file we have the version for placeholder
mysqlversion=1.0.0-SNAPSHOT

with this configuration, I start to see the errors below.

ERROR c.g.d.c.async.ResultCallbackTemplate - Error during callback com.github.dockerjava.api.exception.BadRequestException: {"message":"invalid reference format"}
	at org.testcontainers.dockerclient.transport.okhttp.OkHttpInvocationBuilder.execute(OkHttpInvocationBuilder.java:277)
	at org.testcontainers.dockerclient.transport.okhttp.OkHttpInvocationBuilder.lambda$executeAndStream$3(OkHttpInvocationBuilder.java:303)
	at java.lang.Thread.run(Thread.java:748)

WARN  o.t.c.DockerComposeContainer - Failed to pull image 'eu-west-1.amazonaws.com/content-delivery/mysql:${mysqlversion}'. Exception message was {"message":"invalid reference format"}

If I put version instead of the placeholder all works fine.
Before the update, we were using 1.12.1 version and that version does not have any problems with this type of configuration.

So, basically this is an issue with the current version.

Start at DockerComposeContainer's image-pull handling and reproduce the reported setup with a version placeholder in docker-compose.yml and its value in .env. Compare behavior between testcontainers 1.12.1 and 1.12.5, and consider the issue done when the placeholder resolves to a valid image reference during pulls.