Add junit-xml package to test image as this will be used to generate …

…test xml outputs (kubeflow#110)

Update Pipfile and lock file to reflect this

images/Dockerfile

@@ -107,11 +107,13 @@ RUN cd /tmp && \
 COPY ./Pipfile ./Pipfile.lock /tmp/
 
 # Install various python libraries for both Python 2 and 3 (for now)
+# Don't upgrade pip for now because it seems to be broken
+# https://github.com/pypa/pip/issues/5240
 RUN cd /tmp/ && \
-    pip install -U pip wheel && \
-    pip install pipenv && \
+    pip2 install -U wheel && \
+    pip2 install pipenv && \
     pipenv install --system --two && \
-    pip3 install -U pip wheel && \
+    pip3 install -U wheel && \
     pip3 install pipenv && \
     pipenv install --system --three
 

images/Pipfile

@@ -1,12 +1,9 @@
 [[source]]
-
 url = "https://pypi.python.org/simple"
 verify_ssl = true
 name = "pypi"
 
-
 [packages]
-
 astroid = "==1.6.1"
 cachetools = "==2.0.1"
 certifi = "==2018.1.18"
@@ -48,7 +45,6 @@ uritemplate = "==3.0.0"
 "urllib3" = "==1.22"
 websocket-client = "==0.40.0"
 wrapt = "==1.10.11"
-
+junit-xml = "==1.8"
 
 [dev-packages]
-