Update Dockerfile to work with Ergo naming change

Dockerfile

-## build Oragono
+## build Ergo
 FROM golang:1.16-alpine AS build-env
 
 RUN apk add --no-cache git make curl sed
 
-# copy oragono
-RUN mkdir -p /go/src/github.com/oragono/oragono
-WORKDIR /go/src/github.com/oragono/oragono
-ADD . /go/src/github.com/oragono/oragono/
+# copy ergo
+RUN mkdir -p /go/src/github.com/ergochat/ergo
+WORKDIR /go/src/github.com/ergochat/ergo
+ADD . /go/src/github.com/ergochat/ergo/
 
 # modify default config file so that it doesn't die on IPv6
 # and so it can be exposed via 6667 by default
-run sed -i 's/^\(\s*\)\"127.0.0.1:6667\":.*$/\1":6667":/' /go/src/github.com/oragono/oragono/default.yaml
-run sed -i 's/^\s*\"\[::1\]:6667\":.*$//' /go/src/github.com/oragono/oragono/default.yaml
+run sed -i 's/^\(\s*\)\"127.0.0.1:6667\":.*$/\1":6667":/' /go/src/github.com/ergochat/ergo/default.yaml
+run sed -i 's/^\s*\"\[::1\]:6667\":.*$//' /go/src/github.com/ergochat/ergo/default.yaml
 
 # compile
 RUN make
 
 
 
-## run Oragono
+## run Ergo
 FROM alpine:3.9
 
 # metadata
 LABEL maintainer="daniel@danieloaks.net"
-LABEL description="Oragono is a modern, experimental IRC server written in Go"
+LABEL description="Ergo is a modern, experimental IRC server written in Go"
 
 # install latest updates and configure alpine
 RUN apk update
 
 # oragono itself
 RUN mkdir -p /ircd-bin
-COPY --from=build-env /go/bin/oragono /ircd-bin
-COPY --from=build-env /go/src/github.com/oragono/oragono/languages /ircd-bin/languages/
-COPY --from=build-env /go/src/github.com/oragono/oragono/default.yaml /ircd-bin/default.yaml
+COPY --from=build-env /go/bin/ergo /ircd-bin
+COPY --from=build-env /go/src/github.com/ergochat/ergo/languages /ircd-bin/languages/
+COPY --from=build-env /go/src/github.com/ergochat/ergo/default.yaml /ircd-bin/default.yaml
 
 COPY distrib/docker/run.sh /ircd-bin/run.sh
 RUN chmod +x /ircd-bin/run.sh
 WORKDIR /ircd
 
 # default motd
-COPY --from=build-env /go/src/github.com/oragono/oragono/oragono.motd /ircd/oragono.motd
+COPY --from=build-env /go/src/github.com/ergochat/ergo/ergo.motd /ircd/ergo.motd
 
 # launch
 ENTRYPOINT ["/ircd-bin/run.sh"]