Install acme.sh using online archive

Running `acme.sh --install` apparently only copies `acme.sh` itself.
This seems odd, since that's just copying a single file.  I assumed that
the `--install` options also installed the hook scripts, but there is
actually a separate option for that: `--install-online`.

Containerfile

@@ -18,7 +18,7 @@ RUN curl -fL -o /tmp/acme.sh https://raw.githubusercontent.com/acmesh-official/a
 	mkdir -p /usr/local/acme.sh && \
 	cd /tmp && \
 	sh acme.sh \
-		--install \
+		--install-online \
 		--home /usr/local/acme.sh \
 		--config-home /acme.sh \
 		--no-cron \