use latest onnx in test matrix

Author: nbcsm

ci_build/azure_pipelines/pretrained_model_test-matrix.yml

@@ -5,7 +5,6 @@ jobs:
   parameters:
     platforms: ['linux', 'windows', 'mac']
     tf_versions: ['1.12', '1.11', '1.10', '1.9', '1.8', '1.7', '1.6', '1.5']
-    onnx_versions: ['1.3']
     onnx_opsets: ['8', '7']
     onnx_backends:
       onnxruntime: ['0.2.1']

ci_build/azure_pipelines/unit_test-matrix.yml

@@ -5,7 +5,6 @@ jobs:
   parameters:
     platforms: ['linux', 'windows', 'mac']
     tf_versions: ['1.12', '1.11', '1.10', '1.9', '1.8', '1.7', '1.6', '1.5']
-    onnx_versions: ['1.3']
     onnx_opsets: ['8', '7']
     onnx_backends:
       onnxruntime: ['0.2.1']