Add monthly releases to CHANGELOG

Signed-off-by: Rajeev Rao <rajeevrao@nvidia.com>

Author: rajeevsrao

CHANGELOG.md

@@ -1,5 +1,52 @@
 # TensorRT OSS Release Changelog
 
+## [20.12](https://github.com/NVIDIA/TensorRT/releases/tag/20.12) - 2020-12-18
+### Added
+- Add configurable input size for TLT MaskRCNN Plugin
+
+### Changed
+- Update symbol export map for plugins
+- Correctly use channel dimension when creating Prelu node
+- Fix Jetson cross compilation CMakefile
+
+### Removed
+- N/A
+
+
+## [20.11](https://github.com/NVIDIA/TensorRT/releases/tag/20.11) - 2020-11-20
+### Added
+- API documentation for [ONNX-GraphSurgeon](https://github.com/NVIDIA/TensorRT/tree/master/tools/onnx-graphsurgeon/docs)
+
+### Changed
+- Support for SM86 in [demoBERT](https://github.com/NVIDIA/TensorRT/tree/master/demo/BERT)
+- Updated NGC checkpoint URLs for [demoBERT](https://github.com/NVIDIA/TensorRT/tree/master/demo/BERT) and [Tacotron2](https://github.com/NVIDIA/TensorRT/tree/master/demo/Tacotron2).
+
+### Removed
+- N/A
+
+
+## [20.10](https://github.com/NVIDIA/TensorRT/releases/tag/20.10) - 2020-10-22
+### Added
+- [Polygraphy](https://github.com/NVIDIA/TensorRT/tree/master/tools/Polygraphy) v0.20.13 - Deep Learning Inference Prototyping and Debugging Toolkit
+- [PyTorch-Quantization Toolkit](https://github.com/NVIDIA/TensorRT/tree/master/tools/pytorch-quantization) v2.0.0
+- Updated BERT plugins for [variable sequence length inputs](https://github.com/NVIDIA/TensorRT/tree/master/demo/BERT#variable-sequence-length)
+- Optimized kernels for sequence lengths of 64 and 96 added
+- Added Tacotron2 + Waveglow TTS demo [#677](https://github.com/NVIDIA/TensorRT/pull/677)
+- Re-enable `GridAnchorRect_TRT` plugin with rectangular feature maps [#679](https://github.com/NVIDIA/TensorRT/pull/679)
+- Update batchedNMS plugin to IPluginV2DynamicExt interface [#738](https://github.com/NVIDIA/TensorRT/pull/738)
+- Support 3D inputs in InstanceNormalization plugin [#745](https://github.com/NVIDIA/TensorRT/pull/745)
+- Added this CHANGELOG.md
+
+### Changed
+- ONNX GraphSurgeon - v0.2.7 with bugfixes, new examples.
+- demo/BERT bugfixes for Jetson Xavier
+- Updated build Dockerfile to cuda-11.1
+- Updated ClangFormat style specification according to TensorRT coding guidelines
+
+### Removed
+- N/A
+
+
 ## [7.2.1](https://docs.nvidia.com/deeplearning/tensorrt/release-notes/tensorrt-7.html#rel_7-2-1) - 2020-10-20
 ### Added
 - [Polygraphy](tools/Polygraphy) v0.20.13 - Deep Learning Inference Prototyping and Debugging Toolkit