Fix docker args

After the change to runtime args in #749 docker broke.

This fixes it.

Dockerfile

@@ -23,4 +23,4 @@ COPY --from=ffmpeg / /
 COPY --from=builder /jellyfin /jellyfin
 EXPOSE 8096
 VOLUME /config /media
-ENTRYPOINT dotnet /jellyfin/jellyfin.dll -programdata /config
+ENTRYPOINT dotnet /jellyfin/jellyfin.dll --datadir /config

Dockerfile.arm

@@ -21,4 +21,4 @@ RUN apt-get update \
 COPY --from=builder /jellyfin /jellyfin
 EXPOSE 8096
 VOLUME /config /media
-ENTRYPOINT dotnet /jellyfin/jellyfin.dll -programdata /config
+ENTRYPOINT dotnet /jellyfin/jellyfin.dll --datadir /config

Dockerfile.arm64

@@ -30,4 +30,4 @@ COPY --from=qemu_extract qemu-* /usr/bin
 COPY --from=builder /jellyfin /jellyfin
 EXPOSE 8096
 VOLUME /config /media
-ENTRYPOINT dotnet /jellyfin/jellyfin.dll -programdata /config
+ENTRYPOINT dotnet /jellyfin/jellyfin.dll --datadir /config