feat(sdk): update new image config via env variables

[Tomcli]

Which issue is resolved by this Pull Request:
Resolves #1335

Description of your changes:

Environment tested:

• Python Version (use python --version):
• Tekton Version (use tkn version):
• Kubernetes Version (use kubectl version):
• OS (e.g. from /etc/os-release):

Checklist:

• The title for your pull request (PR) should follow our title convention. Learn more about the pull request title convention used in this repository.

[Tomcli]

cc @diegolovison, changing the base_step code for all the input and output artifact step probably requires to refactor the code into python class. Can this solution work for you?

In V2 we no longer use step injection as we will migrate all the artifacts/results logic to pull from mlmd directly.

[diegolovison]

Ok

[diegolovison]

Could we do the same for condition_image_name?
In this case, we will have a pattern

[Tomcli]

/assign @yhwang

[Tomcli]

Could we do the same for condition_image_name? In this case, we will have a pattern

Sure. Added in the latest commit.

[yhwang]

/lgtm

[google-oss-prow]

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