How can I include and use a powershell file from another repo - azure-devops

Question

I want to use a generic powershell file in multiple build pipelines from a specific repo. This file I want to use it in my release stages to set our servers to maintenance mode an back to running.
At the moment I checkout the second repo in my build stage. But the DotNetCoreCLI#2 restore task does also a checkout and my powershell file disappears.
steps:
- checkout: templates
- checkout: self
- task: CopyFiles#2
displayName: 'Copy ADC Powershell script to: $(Build.ArtifactStagingDirectory)'
inputs:
SourceFolder: '$(Build.SourcesDirectory)/MYREPONAME/scripts/'
Contents: changestate.ps1
TargetFolder: $(Build.ArtifactsDirectory)
And then my task that runs the script doesn't find my powershell file
- task: PowerShell#2
displayName: 'Set $(Agent.MachineName) to maintenance'
inputs:
targetType: filePath
filePath: '$(System.ArtifactsDirectory)/${{ parameters.artifactName }}/changestate.ps1'
arguments: '-server $(AGENT.MACHINENAME) -state "maintenance"'
Has anyone maybe a better idea how can I do that?
Thanks for help.
Update: Solved in this way
I used a seperate stage and the publish task
- checkout: templates
- task: CopyFiles#2
displayName: 'Copy ADC Powershell script to: $(Build.ArtifactStagingDirectory)'
inputs:
SourceFolder: '$(Build.SourcesDirectory)/scripts/'
Contents: '*.ps1'
TargetFolder: $(Build.ArtifactStagingDirectory)
- task: PublishBuildArtifacts#1
displayName: "Publish artifact"
inputs:
pathtoPublish: '$(Build.ArtifactStagingDirectory)'
artifactName: '${{ parameters.artifactName }}'