Fix the docker build

Dockerfile

@@ -12,14 +12,15 @@ RUN apt-get update && \
     unzip -d /usr/local protoc.zip && rm protoc.zip && \
     locale-gen en_US.UTF-8 && \
     export PATH=/usr/lib/go-1.10/bin:$PATH && \
-    go get -v -d gopkg.in/src-d/hercules.v4/... && \
-    cd /root/src/gopkg.in/src-d/hercules.v4 && \
+    git clone --single-branch --branch v4.7.0 --depth 1 https://github.com/src-d/go-git /root/src/gopkg.in/src-d/go-git.v4 && \
+    go get -v -d gopkg.in/src-d/hercules.v5/... && \
+    cd /root/src/gopkg.in/src-d/hercules.v5 && \
     export CGO_CXXFLAGS=-std=c++14 && \
     curl -L "https://storage.googleapis.com/tensorflow/libtensorflow/libtensorflow-cpu-$(go env GOOS)-x86_64-1.7.0.tar.gz" | tar -C /usr/local -xz && \
     make && \
     rm /usr/local/bin/protoc && rm /usr/local/readme.txt && rm -rf /usr/local/include/google && \
     cp /root/bin/hercules /usr/local/bin && \
-    cp -r /root/src/gopkg.in/src-d/hercules.v4/*.py /root/src/gopkg.in/src-d/hercules.v4/internal /usr/local/bin && \
+    cp -r /root/src/gopkg.in/src-d/hercules.v5/*.py /root/src/gopkg.in/src-d/hercules.v5/internal /usr/local/bin && \
     sed -i 's/parser.add_argument("--backend",/parser.add_argument("--backend", default="Agg",/' /usr/local/bin/labours.py && \
     echo '#!/bin/bash\n\
 \n\
@@ -28,7 +29,7 @@ echo "	$@"\n\
 echo\n\' > /browser && \
     chmod +x /browser && \
     curl https://bootstrap.pypa.io/get-pip.py | python3 && \
-    pip3 install --no-cache-dir --no-build-isolation -r /root/src/gopkg.in/src-d/hercules.v4/requirements.txt https://github.com/mind/wheels/releases/download/tf1.7-cpu/tensorflow-1.7.0-cp36-cp36m-linux_x86_64.whl && \
+    pip3 install --no-cache-dir --no-build-isolation -r /root/src/gopkg.in/src-d/hercules.v5/requirements.txt https://github.com/mind/wheels/releases/download/tf1.7-cpu/tensorflow-1.7.0-cp36-cp36m-linux_x86_64.whl && \
     rm -rf /root/* && \
     apt-get remove -y software-properties-common golang-1.10-go python3-dev libyaml-dev libxml2-dev curl git make unzip g++ && \
     apt-get remove -y *-doc *-man && \