docker: run get-secret.py with python3

taskcluster/docker/base/Dockerfile

@@ -34,9 +34,8 @@ RUN apt-get update -qq \
                           expect \
                           git \
                           curl \
-                          python \
-                          python-pip \
                           python3 \
+                          python3-pip \
                           python3-yaml \
                           locales \
                           tzdata \
@@ -44,9 +43,8 @@ RUN apt-get update -qq \
 			  mercurial \
     && apt-get clean
 
-RUN pip install --upgrade pip
-# TODO update to python3 so we can use newer taskcluster
-RUN pip install taskcluster==44.2.2
+RUN pip3 install --upgrade pip
+RUN pip install taskcluster
 
 RUN locale-gen "$LANG"
 

taskcluster/docker/visual-metrics/Dockerfile

@@ -10,9 +10,7 @@ RUN apt-get update -qq && \
       imagemagick \
       pyssim \
       python \
-      python-pil \
-      python3 \
-      python3-pip
+      python-pil
 
 WORKDIR /builds/worker
 

taskcluster/scripts/get-secret.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this