Removing 'ImageVersion' as an env var as we already use 'IMAGE_VERSION'

[jmos5156]

Description

Improvement.

See related issue item #2508

This is mainly code clean up in relation to the new install scripts. We are setting two environment variables with the same result but written in two different ways IMAGE_VERSION and ImageVersion. After looking through the code (functions, modules, and scripts) the only place where ImageVersion is used happens to be in the SoftwareReport.Generator. This PR simply changes this to keep to one set on common env vars using the same format.

Related issue:

Check list

• [*] Related issue / work item is attached
• Tests are written (if applicable)
• Documentation is updated (if applicable)
• [*] Changes are tested and related VM images are successfully generated

[al-cheb]

1. Please leave ImageVersion as is
2. Move setx to the https://github.com/actions/virtual-environments/blob/main/images/win/scripts/Installers/Initialize-VM.ps1 (https://github.com/actions/virtual-environments/pull/2457/files#r560108904)
3. Get rid of "IMAGE_VERSION={{user image_version}}",

[jmos5156]

Hi @al-cheb.
I see what you mean now. I'll update this PR.
However, to make sure I get this right should ImageVersion still be changed to IMAGE_VERSION even though we move it to Initialize-VM.ps1?

IMAGE_VERSION is used throughout the codebase.

ImageVersion is only used in the SoftwareReport Generator script.

[al-cheb]

@jmos5156 , It was request from a customer - #345 to add ImageVersion env variable on Windows images. If you delete it it will impact on all builds which use ImageVersion env variable.

[jmos5156]

Hi guys wondering if this could be reviewed?

[AlenaSviridenko]

/azp run windows2016, windows2019

[azure-pipelines]

Azure Pipelines successfully started running 2 pipeline(s).

[al-cheb]

@jmos5156, Please merge the latest changes from main branch to start an image generation process.

[jmos5156]

I have merged the latest changes from the main branch into this PR.

[AlenaSviridenko]

/azp run windows2016, windows2019

[azure-pipelines]

Azure Pipelines successfully started running 2 pipeline(s).

[jmos5156]

Are we ok to approve this now?

[AlenaSviridenko]

Merging this one, thanks for contribution!