update yamato tests for 2020.1

.yamato/com.unity.ml-agents-test.yml

 test_editors:
   - version: 2019.4
     enableCodeCoverage: !!bool true
-    # We want some scene tests to run in the DevProject, but packages there only support 2019+
+    # We want some scene tests to run in the DevProject, but packages there only support 2020+
+    enableCodeCoverage: !!bool true
+    testProject: DevProject
+    enableNoDefaultPackages: !!bool true
+  - version: 2021.1
     enableCodeCoverage: !!bool true
     testProject: DevProject
     enableNoDefaultPackages: !!bool true

.yamato/test_versions.metafile

     extra_test: gym
   - version: 2020.3
     extra_test: sensor
-# TODO change to 2021.1 soon
-  - version: 2020.2
+  - version: 2021.1
     extra_test: llapi