Update build script vmImage to latest (#269)

Author: Arkatufus

build-system/linux-pr-validation.yaml

@@ -18,14 +18,14 @@ jobs:
     parameters:
       name: 'net_core_tests_linux'
       displayName: '.NET Core Unit Tests (Linux)'
-      vmImage: 'ubuntu-18.04'
+      vmImage: 'ubuntu-latest'
       scriptFileName: ./build.sh
       scriptArgs: runTestsNetCore
 
   - template: azure-pipeline.template.yaml
     parameters:
       name: 'net_5_tests_linux'
       displayName: '.NET 5 Unit Tests (Linux)'
-      vmImage: 'ubuntu-18.04'
+      vmImage: 'ubuntu-latest'
       scriptFileName: ./build.sh
       scriptArgs: runTestsNet

build-system/windows-pr-validation.yaml

@@ -18,31 +18,31 @@ jobs:
     parameters:
       name: 'netfx_tests_windows'
       displayName: '.NET Framework Unit Tests (Windows)'
-      vmImage: 'windows-2019'
+      vmImage: 'windows-latest'
       scriptFileName: build.cmd
       scriptArgs: runTests
 
   - template: azure-pipeline.template.yaml
     parameters:
       name: 'net_core_tests_windows'
       displayName: '.NET Core Unit Tests (Windows)'
-      vmImage: 'windows-2019'
+      vmImage: 'windows-latest'
       scriptFileName: build.cmd
       scriptArgs: runTestsNetCore
 
   - template: azure-pipeline.template.yaml
     parameters:
       name: 'net_5_tests_windows'
       displayName: '.NET 5 Unit Tests (Windows)'
-      vmImage: 'windows-2019'
+      vmImage: 'windows-latest'
       scriptFileName: build.cmd
       scriptArgs: runTestsNet
 
   - template: azure-pipeline.template.yaml
     parameters:
       name: 'nuget_pack'
       displayName: 'NuGet Pack'
-      vmImage: 'windows-2019'
+      vmImage: 'windows-latest'
       scriptFileName: build.cmd
       scriptArgs: CreateNuget nugetprerelease=dev
       outputDirectory: 'bin/nuget'