Use Python 3.10 (#1326)

.taskcluster.yml

@@ -33,9 +33,9 @@ tasks:
       workerType: ci
       payload:
         maxRunTime: 3600
-        image: python:3.7
+        image: python:3.10
         env:
-          TOX_ENV: py37
+          TOX_ENV: py310
           COVERALLS_REPO_TOKEN: VWnjgqWLHfmgSQMJPFdIRYIG5ontiAGl6
         command:
           - "/bin/bash"

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py37
+envlist = py310
 skipsdist = True
 
 [testenv]