Update branding to 3.1.15 (#31577)

* Update branding to 3.1.15

Update Ubuntu 16.04 to 18.04

* Remove obsolete groovy code

Author: John Luo

.azure/pipelines/ci.yml

@@ -266,7 +266,7 @@ stages:
             arguments: -ConfigFile $(Build.SourcesDirectory)/NuGet.config -Password $Env:Token
           env:
             Token: $(dn-bot-dnceng-artifact-feeds-rw)
-            
+
       - script: ./build.cmd
                 -ci
                 -arch arm64
@@ -296,7 +296,7 @@ stages:
                 $(_InternalRuntimeDownloadArgs)
                 /bl:artifacts/log/Release/Build.Installers.Arm64.binlog
         displayName: Build Arm64 Installers
-        
+
       # A few files must also go to the VS package feed.
       - ${{ if and(ne(variables['System.TeamProject'], 'public'), notin(variables['Build.Reason'], 'PullRequest')) }}:
         - task: NuGetCommand@2
@@ -661,7 +661,7 @@ stages:
     parameters:
       condition: ne(variables['SkipTests'], 'true')
       jobName: Linux_Test
-      jobDisplayName: "Test: Ubuntu 16.04 x64"
+      jobDisplayName: "Test: Ubuntu 18.04 x64"
       agentOs: Linux
       isTestingJob: true
       buildArgs: --all --test "/p:RunTemplateTests=false"  $(_InternalRuntimeDownloadArgs)
@@ -699,7 +699,7 @@ stages:
     displayName: 'Test: Linux Source Build'
     container: centos:7
     pool:
-      vmImage: 'ubuntu-16.04'
+      vmImage: 'ubuntu-18.04'
     variables:
       DotNetCoreSdkDir: $(Agent.ToolsDirectory)/dotnet
       # This isn't needed in the path because build does not need to _use_ global tools.

.azure/pipelines/jobs/default-build.yml

@@ -91,7 +91,7 @@ jobs:
       ${{ if eq(parameters.agentOs, 'macOS') }}:
         vmImage: macOS-10.14
       ${{ if eq(parameters.agentOs, 'Linux') }}:
-        vmImage: ubuntu-16.04
+        vmImage: ubuntu-18.04
       ${{ if eq(parameters.agentOs, 'Windows') }}:
         ${{ if eq(variables['System.TeamProject'], 'public') }}:
           name: NetCorePublic-Pool

eng/Versions.props

@@ -8,8 +8,8 @@
   <PropertyGroup Label="Version settings">
     <AspNetCoreMajorVersion>3</AspNetCoreMajorVersion>
     <AspNetCoreMinorVersion>1</AspNetCoreMinorVersion>
-    <AspNetCorePatchVersion>14</AspNetCorePatchVersion>
-    <ValidateBaseline>true</ValidateBaseline>
+    <AspNetCorePatchVersion>15</AspNetCorePatchVersion>
+    <ValidateBaseline>false</ValidateBaseline>
     <PreReleasePreviewNumber>0</PreReleasePreviewNumber>
     <ComponentsWebAssemblyMajorVersion>3</ComponentsWebAssemblyMajorVersion>
     <ComponentsWebAssemblyMinorVersion>2</ComponentsWebAssemblyMinorVersion>