Cleanup kivy test recipe:

- reuse requirements, follow KivyMD doc
  - remove unneeded packages
  - explicitly run python3 in test.sh
  - use pip for installation

.buildbot/kivy/Dockerfile

@@ -1,26 +1,16 @@
 # A container for buildbot
 FROM ubuntu:bionic AS kivy
-# FROM ubuntu:20.04 AS buildbot-bionic
 
 ENV DEBIAN_FRONTEND=noninteractive
 
 RUN apt-get update
 
-RUN apt-get -y install sudo
-
-RUN apt-get install -yq python-setuptools \
-    python-setuptools libssl-dev libpq-dev python-prctl python-dev \
-    python-virtualenv python-pip virtualenv \
-    libjpeg-dev zlib1g-dev python3-dev \
-    python3-virtualenv \
-    python3-pip \
-    wget \
-    build-essential libcap-dev libmtdev-dev xvfb xclip git python3-opencv
+RUN apt-get install -yq \
+    build-essential libcap-dev libssl-dev \
+    libmtdev-dev libpq-dev \
+    python3-dev python3-pip python3-virtualenv \
+    xvfb
 
 RUN ln -sf /usr/bin/python3 /usr/bin/python
 
-RUN pip3 install Cython Pillow pyzbar telenium
-
 RUN pip3 install --upgrade setuptools pip
-
-RUN pip3 install -e git+https://github.com/kivymd/KivyMD#egg=kivymd

.buildbot/kivy/build.sh

@@ -1,3 +1,5 @@
 #!/bin/sh
 
-python setup.py install --user
+pip3 install -r kivy-requirements.txt
+
+pip3 install .

.buildbot/kivy/test.sh

@@ -1,3 +1,3 @@
 #!/bin/bash
 
-xvfb-run python tests-kivy.py
+xvfb-run python3 tests-kivy.py

kivy-requirements.txt

@@ -1,5 +1,5 @@
 kivy-garden.qrcode
--e git+https://github.com/kivymd/KivyMD#egg=kivymd
+https://github.com/kivymd/KivyMD/archive/master.zip
 opencv-python
 pyzbar
-telenium
+telenium