Merge in 'release/6.0' changes

Author: dotnet-bot

.azure/pipelines/helix-matrix.yml

@@ -28,7 +28,7 @@ jobs:
     jobName: Helix_matrix_x64
     jobDisplayName: 'Tests: Helix full matrix x64'
     agentOs: Windows
-    timeoutInMinutes: 480
+    timeoutInMinutes: 300
     steps:
     # Build the shared framework
     - script: ./eng/build.cmd -ci -nobl -all -pack -arch x64