Upgrade both Windows and Ubuntu to run on their latest versions (#55)

Upgrade both Windows and Ubuntu to run on their latest versions

Author: Aaronontheweb

build-system/pr-validation.yaml

@@ -21,20 +21,20 @@ jobs:
     parameters:
       name: 'windows_pr'
       displayName: 'Windows PR Validation'
-      vmImage: 'vs2017-win2016'
+      vmImage: 'windows-latest'
       scriptFileName: build.cmd
       scriptArgs: all customNuGetSource=$(sdkbinPreAuthenticated)
   - template: azure-pipeline.template.yaml
     parameters:
       name: 'linux_pr'
       displayName: 'Linux PR Validation'
-      vmImage: 'ubuntu-16.04'
+      vmImage: 'ubuntu-latest'
       scriptFileName: ./build.sh
       scriptArgs: all customNuGetSource=$(sdkbinPreAuthenticated)
   - template: azure-pipeline.template.yaml
     parameters:
       name: 'docker_build'
       displayName: 'Docker Build'
-      vmImage: 'ubuntu-16.04'
+      vmImage: 'ubuntu-latest'
       scriptFileName: ./build.sh
-      scriptArgs: Docker customNuGetSource=$(sdkbinPreAuthenticated)
+      scriptArgs: Docker customNuGetSource=$(sdkbinPreAuthenticated)