Replace MAINTAINER with LABEL (#1547)
Replace MAINTAINER with LABEL (#1547)

Closes https://github.com/loklak/loklak_server/issues/1546
singhpratyush/loklak_server,singhpratyush/loklak_server,loklak/loklak_server,loklak/loklak_server,loklak/loklak_server,loklak/loklak_server,singhpratyush/loklak_server,loklak/loklak_server,loklak/loklak_server,loklak/loklak_server,singhpratyush/loklak_server,singhpratyush/loklak_server,singhpratyush/loklak_server,singhpratyush/loklak_server