Azure Pull Request Azure Devops - You must provide a value expression following the operator

Question

I am  running this YAML file:

trigger:
- none
## notes 
pool:
  vmImage: ubuntu-latest

## Job to calculate semantic version
jobs:
  - job: CalculateVersion
    displayName: Semantic versioning
    
    steps:
      # Checkout with persist credentials
      - checkout: self
        persistCredentials: true

      # Install GitVersion
      - task: gitversion/setup@0
        displayName: Install GitVersion
        inputs:
          versionSpec: '5.x'

      # Retrieve Pull Request Description
      - task: PullRequestDescription@0
        name: RetrievePullRequestDescription
        displayName: Retrieve Pull Request description
        inputs:
          action: 'view'
          outputVariable: 'PullRequest.DescriptionContent'
          isOutput: true
          stripIdentifiers: false

      # Add git commit message that will be picked up by GitVersion ("+semver: patch/minor/major")
      # Depending on the Pull Request description, where the developer has marked the type of change
      - task: PowerShell@2
        displayName: Add git commit message for SemVer
        inputs:
          targetType: inline
          script: |
            Write-Host "Configuring git author info.." -ForegroundColor Cyan
          
            git config user.email "alan.haro@datashieldprotect.com"
            git config user.name "alan.haro"
            Write-Host "Doing git checkout..." -ForegroundColor Cyan
            git checkout -b $("$(System.PullRequest.SourceBranch)".replace('refs/heads/creating-git-tags', ''))
            Write-Host "Checking Pull Request description..." -ForegroundColor Cyan
            $PRdesc = "$(RetrievePullRequestDescription.PullRequest.DescriptionContent)"
            if ($PRdesc -match '(\[x\] \bFix\b)') {
              Write-Host "Adding git (empty) commit message to mark this branch as a 'patch' SemVer increment." -ForegroundColor Cyan
              git commit -a -m "+semver: patch [skip azurepipelines]" --allow-empty
            } elseif ($PRdesc -match '(\[x\] \bFeature\b)') {
              Write-Host "Adding git (empty) commit message to mark this branch as a 'minor' SemVer increment." -ForegroundColor Cyan
              git commit -a -m "+semver: minor [skip azurepipelines]" --allow-empty
            } elseif ($PRdesc -match '(\[x\] \bBig\b)') {
              Write-Host "Adding git (empty) commit message to mark this branch as a 'major' SemVer increment." -ForegroundColor Cyan
              git commit -a -m "+semver: major [skip azurepipelines]" --allow-empty
            } else {
              Write-Host "##vso[task.LogIssue type=error;]Please select the type of change in the Pull Request description, and Re-queue the validation." -ForegroundColor Cyan
              $PRdesc
              exit 1
            }
            Write-Host "Doing git push.." -ForegroundColor Cyan
            git push --set-upstream origin $("$(System.PullRequest.SourceBranch)".replace('refs/heads/', ''))
            Write-Host "Done." -ForegroundColor Cyan
          
      # Determine the semantic version & test test
      - task: gitversion/execute@0
        displayName: Determine SemVer

I  passed the following command in the comments from the new PR to make sure that my YAML code runs well.

git commit -a -m "+'semver: minor [skip azurepipelines]'" --allow-empty

After that I got this error:

" You must provide a value expression following the '+' operator."

what can I do to prevent this type of error message?