🐳 Update Dockerfile to use 1.9.1

docker/Dockerfile

@@ -6,7 +6,7 @@ RUN apt update && apt install -y --no-install-recommends make g++ curl git
 # Install mwoffliner
 RUN apt install -y --no-install-recommends imagemagick
 RUN npm --global config set user root
-RUN npm install -g mwoffliner@1.8.6
+RUN npm install -g mwoffliner@1.9.1
 RUN apt remove -y make g++
 
 # Boot commands