add table in readme (#5816)

Author: maryamhonari

com.unity.ml-agents.extensions/CHANGELOG.md

@@ -1,5 +1,5 @@
 # Changelog
 This changelog isn't used; please add to the `com.unity.ml-agents` changelog instead.
 
-## [Unreleased]
+## [0.6.1-preview]
  * Initial version

docs/Readme.md

@@ -63,9 +63,9 @@ under active development and may be unstable. A few helpful guidelines:
 
 | **Version** | **Release Date** | **Source** | **Documentation** | **Download** | **Python Package** | **Unity Package** |
 |:-------:|:------:|:-------------:|:-------:|:------------:|:------------:|:------------:|
+| **Release 20** | **November 21, 2022** | **[source](https://github.com/Unity-Technologies/ml-agents/tree/release_20)** | **[docs](https://github.com/Unity-Technologies/ml-agents/tree/release_20_docs/docs/Readme.md)** | **[download](https://github.com/Unity-Technologies/ml-agents/archive/release_20.zip)** | **[0.30.0](https://pypi.org/project/mlagents/0.30.0/)** | **[2.3.0](https://docs.unity3d.com/Packages/[email protected]/manual/index.html)** |
 | **main (unstable)** | -- | [source](https://github.com/Unity-Technologies/ml-agents/tree/main) | [docs](https://github.com/Unity-Technologies/ml-agents/tree/main/docs/Readme.md) | [download](https://github.com/Unity-Technologies/ml-agents/archive/main.zip) | -- | -- |
-| **Release 19** | **January 14, 2022** | **[source](https://github.com/Unity-Technologies/ml-agents/tree/release_20)** | **[docs](https://github.com/Unity-Technologies/ml-agents/tree/release_20_docs/docs/Readme.md)** | **[download](https://github.com/Unity-Technologies/ml-agents/archive/release_20.zip)** | **[0.28.0](https://pypi.org/project/mlagents/0.28.0/)** | **[2.2.1](https://docs.unity3d.com/Packages/[email protected]/manual/index.html)** |
-| **Verified Package 1.0.8** | **May 26, 2021** | **[source](https://github.com/Unity-Technologies/ml-agents/tree/com.unity.ml-agents_1.0.8)** | **[docs](https://github.com/Unity-Technologies/ml-agents/blob/release_20_verified_docs/docs/Readme.md)** | **[download](https://github.com/Unity-Technologies/ml-agents/archive/com.unity.ml-agents_1.0.8.zip)** | **[0.16.1](https://pypi.org/project/mlagents/0.16.1/)** | **[1.0.8](https://docs.unity3d.com/Packages/[email protected]/manual/index.html)** |
+| **Verified Package 1.0.8** | **May 26, 2021** | **[source](https://github.com/Unity-Technologies/ml-agents/tree/com.unity.ml-agents_1.0.8)** | **[docs](https://github.com/Unity-Technologies/ml-agents/blob/release_2_verified_docs/docs/Readme.md)** | **[download](https://github.com/Unity-Technologies/ml-agents/archive/com.unity.ml-agents_1.0.8.zip)** | **[0.16.1](https://pypi.org/project/mlagents/0.16.1/)** | **[1.0.8](https://docs.unity3d.com/Packages/[email protected]/manual/index.html)** |
 
 If you are a researcher interested in a discussion of Unity as an AI platform,
 see a pre-print of our

utils/make_readme_table.py

@@ -137,6 +137,7 @@ def pypi_link(self):
     ReleaseInfo("release_17", "2.0.0", "0.26.0", "April 22, 2021"),
     ReleaseInfo("release_18", "2.1.0", "0.27.0", "June 9, 2021"),
     ReleaseInfo("release_19", "2.2.1", "0.28.0", "January 14, 2022"),
+    ReleaseInfo("release_20", "2.3.0", "0.30.0", "November 21, 2022"),
     # Verified releases
     ReleaseInfo("", "1.0.8", "0.16.1", "May 26, 2021", is_verified=True),
     ReleaseInfo("", "1.0.7", "0.16.1", "March 8, 2021", is_verified=True),