Fix tox passenv values

Author: jeylau

tox.ini

@@ -8,22 +8,23 @@ python =
     3.8: py38
     3.9: py39
     3.10: py310
-    
+
 [gh-actions:env]
 PLATFORM =
     ubuntu-latest: linux
     macos-latest: macos
     windows-latest: windows
 
 [testenv]
-platform = 
+platform =
     macos: darwin
     linux: linux
     windows: win32
-passenv = 
+passenv =
     CI
     GITHUB_ACTIONS
-    DISPLAY XAUTHORITY
+    DISPLAY
+    XAUTHORITY
     NUMPY_EXPERIMENTAL_ARRAY_FUNCTION
     PYVISTA_OFF_SCREEN
 extras =