Update Dockerfile: make -j 4 changed to make -d for debugging

docker/Dockerfile

@@ -37,7 +37,7 @@ RUN git clone --branch v3.3.0 https://github.com/soedinglab/hh-suite.git /tmp/hh
     && mkdir /tmp/hh-suite/build
 WORKDIR /tmp/hh-suite/build
 RUN cmake -DCMAKE_INSTALL_PREFIX=/opt/hhsuite .. \
-    && make -j 4 && make install \
+    && make -d && make install \
     && ln -s /opt/hhsuite/bin/* /usr/bin \
     && rm -rf /tmp/hh-suite