modules/Dockerfile.alpine: install curl

Not all alpine-based images have curl that's needed to fetch the sources
of modules built.

modules/Dockerfile.alpine

@@ -15,7 +15,7 @@ COPY ./ /modules/
 RUN apk update \
     && apk add linux-headers openssl-dev pcre2-dev zlib-dev openssl abuild \
                musl-dev libxslt libxml2-utils make mercurial gcc unzip git \
-               xz g++ coreutils \
+               xz g++ coreutils curl \
     # allow abuild as a root user \
     && printf "#!/bin/sh\\nSETFATTR=true /usr/bin/abuild -F \"\$@\"\\n" > /usr/local/bin/abuild \
     && chmod +x /usr/local/bin/abuild \