Work CI-CD

- Add task to count artifacts in order to skip following tasks if there are none.

***NO_CI***

Author: josesimoes

azure-pipelines.yml

@@ -90,11 +90,26 @@ steps:
     TargetFolder: '$(Build.ArtifactStagingDirectory)'
     flattenFolders: true
 
+# find if there are NuGet artifacts
+- task: PowerShell@2
+  displayName: Count artifacts
+  name: Count_Artifacts
+  inputs:
+    workingDirectory: '$(Build.ArtifactStagingDirectory)'
+    targetType: inline
+    script: |
+      $count = (Get-ChildItem -Path '.' -Filter '*.nupkg' -Recurse).Count
+      Write-Host $count + ' NuGet packages found'
+
+      # set variable to forward 
+      echo "##vso[task.setvariable variable=NUGET_COUNT;isOutput=true]$count"
+
 - task: DotNetCoreCLI@2
   displayName: Install SignTool tool
   condition: >-
     and(
       succeeded(),
+      gt(variables.NUGET_COUNT, 0),
       eq(variables['System.PullRequest.PullRequestId'], '')
     )
   inputs:
@@ -115,9 +130,14 @@ steps:
     --descriptionUrl "https://github.com/$env:Build_Repository_Name"
   displayName: Sign packages
   continueOnError: true
-  condition: and( succeeded(), eq(variables['System.PullRequest.PullRequestId'], '') )
+  condition: >-
+    and(
+      succeeded(),
+      gt(variables.NUGET_COUNT, 0),
+      eq(variables['System.PullRequest.PullRequestId'], '')
+    )
   
-# publish artifacts (only possible if this is not a PR originated on a fork)
+# publish artifacts
 - task: PublishBuildArtifacts@1
   condition: succeeded()
   displayName: Publish deployables artifacts
@@ -136,6 +156,7 @@ steps:
   condition: >-
     and(
       succeeded(),
+      gt(variables.NUGET_COUNT, 0),
       eq(variables['System.PullRequest.PullRequestId'], '')
     )
   continueOnError: false
@@ -147,6 +168,7 @@ steps:
   condition: >-
     and(
       succeeded(),
+      gt(variables.NUGET_COUNT, 0),
       eq(variables['System.PullRequest.PullRequestId'], '')
     )
   continueOnError: false
@@ -157,6 +179,7 @@ steps:
   condition: >-
     and(
       succeeded(),
+      gt(variables.NUGET_COUNT, 0),
       eq(variables['System.PullRequest.PullRequestId'], '')
     )
   inputs:
@@ -166,12 +189,13 @@ steps:
     workingDirectory: 'nanoFramework.IoT.Device'
 
 - task: PowerShell@2
+  displayName: Push READMEs to GitHub
   condition: >-
     and(
       succeeded(),
+      gt(variables.NUGET_COUNT, 0),
       eq(variables['System.PullRequest.PullRequestId'], '')
     )
-  displayName: Push READMEs to GitHub
   continueOnError: true
   inputs:
     workingDirectory: 'nanoFramework.IoT.Device'