Update Dockerfile

Dockerfile

@@ -138,7 +138,7 @@ RUN mkdir -p /home/renderer/src \
 # Configure stylesheet
 RUN mkdir -p /home/renderer/src \
  && cd /home/renderer/src \
- && git clone -b master https://github.com/gravitystorm/openstreetmap-carto.git --depth 1 \
+ && git clone --single-branch --branch v5.3.1 https://github.com/gravitystorm/openstreetmap-carto.git --depth 1 \
  && cd openstreetmap-carto \
  && rm -rf .git \
  && npm install -g carto \