Remove document about deprecated onnx-docker (#272)

Signed-off-by: Chun-Wei Chen <jacky82226@gmail.com>

Signed-off-by: Chun-Wei Chen <jacky82226@gmail.com>

Author: jcwchen

README.md

@@ -4,10 +4,6 @@
 
 [Open Neural Network Exchange (ONNX)](https://onnx.ai/) is an open standard format for representing machine learning models. ONNX is supported by [a community of partners](https://onnx.ai/supported-tools) who have implemented it in many frameworks and tools.
 
-These images are available for convenience to get started with ONNX and tutorials on this page
-  * [Docker image for ONNX and Caffe2/PyTorch](pytorch_caffe2_docker.md)
-  * [Docker image for ONNX, ONNX Runtime, and various converters](https://github.com/onnx/onnx-docker/tree/master/onnx-ecosystem)
-
 
 ## Getting ONNX models
 
@@ -104,13 +100,13 @@ Tutorials demonstrating how to use ONNX in practice for varied scenarios across
 ## Other ONNX tools
 
 * [Verifying correctness and comparing performance](tutorials/CorrectnessVerificationAndPerformanceComparison.ipynb)
-* [Example of operating on ONNX protobuf](https://github.com/onnx/onnx/blob/master/onnx/examples/Protobufs.ipynb)
+* [Example of operating on ONNX protobuf](https://github.com/onnx/onnx/blob/main/onnx/examples/Protobufs.ipynb)
 * [Float16 <-> Float32 converter](https://github.com/onnx/onnx-docker/blob/master/onnx-ecosystem/converter_scripts/float32_float16_onnx.ipynb)
 * [Version conversion](tutorials/VersionConversion.md)
 
 
 ## Contributing
 
-We welcome improvements to the convertor tools and contributions of new ONNX bindings. Check out [contributor guide](https://github.com/onnx/onnx/blob/master/docs/CONTRIBUTING.md) to get started.
+We welcome improvements to the convertor tools and contributions of new ONNX bindings. Check out [contributor guide](https://github.com/onnx/onnx/blob/main/docs/CONTRIBUTING.md) to get started.
 
 Use ONNX for something cool? Send the tutorial to this repo by submitting a PR.

pytorch_caffe2_docker.md

@@ -110,7 +110,7 @@ class Graph(object):
     operators).
 
     The set of operators and the inputs/attributes they take
-    is documented at https://github.com/onnx/onnx/blob/master/docs/Operators.md
+    is documented at https://github.com/onnx/onnx/blob/main/docs/Operators.md
 
     Arguments:
         opname (string): The ONNX operator name, e.g., `Abs` or `Add`.

tutorials/PytorchAddExportSupport.md

@@ -2,7 +2,7 @@
 
 ## Version Conversion
 
-The ONNX [Version Converter](https://github.com/onnx/onnx/blob/master/docs/VersionConverter.md) helps convert ONNX models to the version needed by the runtime you are using.
+The ONNX [Version Converter](https://github.com/onnx/onnx/blob/main/docs/VersionConverter.md) helps convert ONNX models to the version needed by the runtime you are using.
 
 Version Conversion for BatchNormalization from opset 8 to 9:
 

tutorials/VersionConversion.md

@@ -3,7 +3,7 @@
 Visualizing an ONNX Model
 =========================
 
-To visualize an ONNX model, we can use the [net drawer tool](https://github.com/onnx/onnx/blob/master/onnx/tools/net_drawer.py). This tool takes in a serialized ONNX model and produces a directed graph representation. The graph contains the following information:
+To visualize an ONNX model, we can use the [net drawer tool](https://github.com/onnx/onnx/blob/main/onnx/tools/net_drawer.py). This tool takes in a serialized ONNX model and produces a directed graph representation. The graph contains the following information:
 
 * Tensors
    * Input/output tensors

tutorials/VisualizingAModel.md

@@ -458,7 +458,7 @@ message TensorShapeProto {
     // Standard denotation can optionally be used to denote tensor
     // dimensions with standard semantic descriptions to ensure
     // that operations are applied to the correct axis of a tensor.
-    // Refer to https://github.com/onnx/onnx/blob/master/docs/DimensionDenotation.md#denotation-definition
+    // Refer to https://github.com/onnx/onnx/blob/main/docs/DimensionDenotation.md#denotation-definition
     // for pre-defined dimension denotations.
     string denotation = 3;
   };
@@ -539,7 +539,7 @@ message TypeProto {
 
   // An optional denotation can be used to denote the whole
   // type with a standard semantic description as to what is
-  // stored inside. Refer to https://github.com/onnx/onnx/blob/master/docs/TypeDenotation.md#type-denotation-definition
+  // stored inside. Refer to https://github.com/onnx/onnx/blob/main/docs/TypeDenotation.md#type-denotation-definition
   // for pre-defined type denotations.
   string denotation = 6;
 }