Merge branch 'master' into fix_convtranspose_channels_first

Author: TomWildenhain-Microsoft

Diff for: ci_build/azure_pipelines/keras2onnx_application_tests.yml

@@ -5,7 +5,7 @@ jobs:
 - job: 'Linux'
   timeoutInMinutes: 180
   pool:
-    vmImage: 'Ubuntu-16.04'
+    vmImage: 'ubuntu-latest'
   strategy:
     matrix:
       Python36-onnx1.5:

Diff for: ci_build/azure_pipelines/keras2onnx_unit_test.yml

@@ -4,7 +4,7 @@ jobs:
 
 - job: 'Linux'
   pool:
-    vmImage: 'Ubuntu-16.04'
+    vmImage: 'ubuntu-latest'
   strategy:
     matrix:
 

Diff for: ci_build/azure_pipelines/templates/combine_test_coverage.yml

@@ -11,7 +11,7 @@ stages:
       CI_ARTIFACT_NAME: '${{ parameters.artifact_name }}'
 
     pool:
-      vmImage: 'ubuntu-16.04'
+      vmImage: 'ubuntu-latest'
 
     steps:
     - task: DownloadBuildArtifacts@0

Diff for: ci_build/azure_pipelines/templates/job_generator.yml

@@ -33,7 +33,7 @@ jobs:
                     ${{ each onnx_opset in parameters.onnx_opsets }}:
                       ${{ format('{0} python{1}{2}{3} tf{4} onnx{5} {6}{7}{8}', platform, python_version, replace(replace(parameters.skip_tflite_tests,'True', ''), 'False', ' tflite'), replace(replace(parameters.skip_tfjs_tests,'True', ''), 'False', ' tfjs'), tf_version, onnx_version, replace(format('opset{0} ', onnx_opset), 'opset ', ''), onnx_backend.key, onnx_backend_version) }}:
                         ${{ if eq(platform, 'linux') }}:
-                          CI_VM_IMAGE: 'ubuntu-16.04'
+                          CI_VM_IMAGE: 'ubuntu-latest'
                         ${{ if eq(platform, 'windows') }}:
                           CI_VM_IMAGE: 'vs2017-win2016'
                         ${{ if eq(platform, 'mac') }}:

Diff for: ci_build/azure_pipelines/trimmed_keras2onnx_application_tests.yml

@@ -5,7 +5,7 @@ jobs:
 - job: 'Linux'
   timeoutInMinutes: 180
   pool:
-    vmImage: 'Ubuntu-16.04'
+    vmImage: 'ubuntu-latest'
   strategy:
     matrix:
       Python36-onnx1.5:

Diff for: ci_build/azure_pipelines/trimmed_keras2onnx_unit_test.yml

@@ -4,7 +4,7 @@ jobs:
 
 - job: 'Linux'
   pool:
-    vmImage: 'Ubuntu-16.04'
+    vmImage: 'ubuntu-latest'
   strategy:
     matrix: