chore: update ci and docs to unity 2021.3 (#1892)

Author: ashwinimurt

.yamato/project.metafile

@@ -41,7 +41,7 @@ projects:
         path: com.unity.netcode.gameobjects
     test_editors:
       - 2020.3
-      - 2021.2
+      - 2021.3
       - trunk
   - name: minimalproject
     path: minimalproject
@@ -57,5 +57,5 @@ projects:
     validate: false
     publish: false
     test_editors:
-      - 2021.2
+      - 2021.3
       - trunk

README.md

@@ -24,7 +24,7 @@ For general questions, networking advice or discussions about Netcode for GameOb
 ### Compatibility
 
 Netcode for GameObjects targets the following Unity versions:
-- Unity 2020.3, 2021.1, and 2021.2
+- Unity 2020.3, 2021.1, 2021.2 and 2021.3
 
 On the following runtime platforms:
 - Windows, MacOS, and Linux

com.unity.netcode.gameobjects/Documentation~/index.md

@@ -16,7 +16,7 @@ See guides below to install Unity Netcode for GameObjects, set up your project,
 ## Requirements
 
 Netcode for GameObjects targets the following Unity versions:
-- Unity 2020.3, 2021.1, and 2021.2
+- Unity 2020.3, 2021.1, 2021.2 and 2021.3
 
 On the following runtime platforms:
 - Windows, MacOS, and Linux