add cheetah

Dockerfile

@@ -32,6 +32,9 @@ RUN \
   apt install -y doxygen && \
   apt install -y jq && \
   rm -rf /var/lib/apt/lists/* && \
+  ln -s /usr/bin/python3 /usr/bin/python && \
+  ln -s /usr/bin/pip3 /usr/bin/pip && \
+  pip install Cheetah3 && \
   cd /tmp && \
   wget $RELEASETOOL_URL && \
   unzip GitlabReleaseTool.zip && \