Bump to Python 3.10 (#784)

* Bump to Python 3.10

* Bump Python in tox.ini as well

.taskcluster.yml

@@ -37,7 +37,7 @@ tasks:
       workerType: ci
       payload:
         maxRunTime: 3600
-        image: python:3.7
+        image: python:3.10
         command:
           - "/bin/bash"
           - "-lcx"

Dockerfile

@@ -1,4 +1,4 @@
-FROM python:3.9-alpine
+FROM python:3.10-alpine
 
 # Add mozci source code and setup instructions
 WORKDIR /src

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 isolated_build = true
-envlist = py37,pre-commit
+envlist = py310,pre-commit
 
 [testenv]
 envdir = {toxworkdir}/env