updated tests to 2020.3.19f1

.yamato/environments.yml

 
 upmci_registry: https://artifactory.prd.cds.internal.unity3d.com/artifactory/api/npm/upm-npm
 
-# sticking to 2019.4.6f1 for testing for now because Linux Editor fails to open PerceptionHDRP on 2019.4.8f1
-# see https://fogbugz.unity3d.com/default.asp?1273518_d68j5lb6eucglb84
-  - version: 2020.3.17f1
+  - version: 2020.3.19f1
-  - version: 2020.3.17f1
+  - version: 2020.3.19f1
-  - version: 2020.3.17f1
+  - version: 2020.3.19f1
-  - version: 2020.3.17f1
+  - version: 2020.3.19f1
 
 publish_platforms:
   - name: win