azure pipeline with bicep files push to acr. uses git diff to only push modified modules

diff.ps1

$version = get-date -Format yyyy-MM-dd
$commit = "$ENV:BUILD_SOURCEVERSION"

# get the latest files changed
$files = $(git diff HEAD HEAD~ --name-only -- *.bicep modules/)
if ($files.count -ge 1) {
  # copy files to staging
  copy-item $files -Destination $ENV:BUILD_ARTIFACTSTAGINGDIRECTORY

  # set a variable and build number
  Write-Host ("##vso[task.setvariable variable=bicepFiles]true")
  write-host ("##vso[build.updatebuildnumber]$($version)")
}

else {
  Write-Host ("##vso[task.setvariable variable=bicepFiles]false")
}

pipeline.yaml

trigger:
- master

name: $(Date:yyyyMMdd)$(Rev:.r)

variables:
  serviceConnectionName: ''

stages:
  - stage: Build
    jobs:
    - job:
      steps:
      - checkout: self
      - task: PowerShell@2
        displayName: 'Get changed or added files'
        inputs:
          targetType: filePath
          filePath: .scripts/diff.ps1
          pwsh: true
          

      - task: PublishPipelineArtifact@1
        displayName: 'Publish files as artifact'
        condition: and(succeeded(), eq(variables.bicepFiles, 'true'))
        inputs: 
          artifact: 'bicep'
          targetPath: '$(Build.ArtifactStagingDirectory)'
          publishLocation: pipeline

      - task: AzureCLI@2
        displayName: 'Validate bicep modules'
        inputs:
          azureSubscription: $(serviceConnectionName)
          addSpnToEnvironment: true
          scriptLocation: scriptPath
          ScriptType: 'pscore'
          scriptPath: .scripts/bicepvalidate.ps1 
  - stage: deploy
    dependsOn: Build
    jobs:
    - deployment: Deploy
      environment: 'bicep-prod'
      displayName: 'Deploy bicep files to registry'
      strategy:
        runOnce:
          deploy:
            steps:
              - checkout: self
              - task: DownloadBuildArtifacts@1
                inputs:
                  artifactName: 'bicep'
                  allowPartiallySucceededBuilds: false
              - task: AzureCLI@2
                displayName: 'Deploy bicep files to ACR'
                inputs:
                  azureSubscription: $(serviceConnectionName)
                  addSpnToEnvironment: true
                  scriptLocation: scriptPath
                  ScriptType: 'pscore'
                  scriptPath: .scripts/publish.ps1

publish.ps1

# publish bicep modules to acr
$version = get-date -Format yyyy-MM-dd

$modules = Get-ChildItem "$env:SYSTEM_ARTIFACTSDIRECTORY" -Include *.bicep -Recurse

foreach ($module in $modules) {
    $name = $module.BaseName
    bicep publish $module.FullName --target "br:myregistry.azurecr.io/modules/${name}:${version}"
}