Update Dockerfile

Update as per my review, change / to | in sed-command that replaces version on footer.

Author: tpanajott

docker/Dockerfile

@@ -40,7 +40,7 @@ COPY --from=build /MQTTManager/build /MQTTManager/build
 COPY docker/web/nspanelmanager/web/templates/footer_template.html docker/web/nspanelmanager/web/templates/footer.html
 COPY docs/tex/manual.pdf docker/web/nspanelmanager/manual.pdf
 
-RUN  sed -i "s/%version%/$VERSION/g" docker/web/nspanelmanager/web/templates/footer.html
+RUN  sed -i "s|%version%|$VERSION|g" docker/web/nspanelmanager/web/templates/footer.html
 
 
 # Update container