fix python package naming in ubuntu

Dockerfile

@@ -12,10 +12,10 @@ RUN \
   apt install -y make && \
   apt install -y openssh-client && \
   apt install -y git && \
-  apt install -y python && \
-  apt install -y python-requests && \
-  apt install -y python-pycodestyle && \
-  apt install -y python-yaml && \
+  apt install -y python-is-python3 && \
+  apt install -y python3-requests && \
+  apt install -y python3-pycodestyle && \
+  apt install -y python3-yaml && \
   apt install -y gpg && \
   apt install -y apt-transport-https && \
   apt install -y wget && \