dockerfile: replace deprecated MAINTAINER instruction (#1663)

Signed-off-by: Takahiro YAMASHITA <[email protected]>

Author: nokute78

Dockerfile

@@ -53,7 +53,7 @@ COPY conf/fluent-bit.conf \
      /fluent-bit/etc/
 
 FROM gcr.io/distroless/cc
-MAINTAINER Eduardo Silva <[email protected]>
+LABEL maintainer="Eduardo Silva <[email protected]>"
 LABEL Description="Fluent Bit docker image" Vendor="Fluent Organization" Version="1.1"
 
 COPY --from=builder /usr/lib/x86_64-linux-gnu/*sasl* /usr/lib/x86_64-linux-gnu/