Fix bad instructions order

pica-oh-my-form/Dockerfile

@@ -12,8 +12,8 @@ RUN apk add --no-cache python=2.7.16-r1 \
 	&& npm cache clean --force
 
 RUN wget -O omf.tar.gz https://github.com/ohmyform/ohmyform/archive/${OHMYFORM_VERSION}.tar.gz \
-  && tar --strip-components=1 -x -f omf.tar.gz -C /opt/app \
   && mkdir -p /opt/app/public/lib \
+  && tar --strip-components=1 -x -f omf.tar.gz -C /opt/app \
   && chown -R ohmyform:ohmyform /opt/app
 
 WORKDIR /opt/app