Correct bionic apt dependency hell...

Installing ethereum wants a particular version of python3-pip but
and earlier step to install mythril may install a newer version of that

Dockerfile

@@ -3,13 +3,17 @@ FROM ubuntu:bionic
 COPY . /opt/mythril
 
 RUN apt-get update \
-  && apt-get install -y software-properties-common \
+  && apt-get install -y \
+     build-essential \
+     python-pip-whl=9.0.1-2 \
+     python3-pip=9.0.1-2 \
+     python3-setuptools \
+     software-properties-common \
   && add-apt-repository -y ppa:ethereum/ethereum \
   && apt-get update \
   && apt-get install -y \
      solc \
      libssl-dev \
-     python3-pip=9.0.1-2 \
      python3-dev \
      pandoc \
      git \