add do-not-prune lable to image rather than container

docker-compose.yml

@@ -66,8 +66,6 @@ services:
       - archives:/app/archives
     environment:
       ApplicationInsights__InstrumentationKey: ${FILTERLISTS_AGENT_APPLICATION_INSIGHTS_INSTRUMENTATION_KEY}
-    labels:
-      do-not-prune:
 
 networks:
   reverse-proxy:

src/FilterLists.Agent/Dockerfile

@@ -4,6 +4,7 @@
 # init base
 FROM mcr.microsoft.com/dotnet/core/aspnet:2.2-alpine as base
 ENTRYPOINT ["dotnet", "FilterLists.Agent.dll"]
+LABEL do-not-prune
 WORKDIR /app
 
 # init build