community/luarocks: use wget instead of curl on recent luarocks versions
The program was previously failing to download manifests due to wget not being shipped by default anymore on Alpine.
To reproduce on versions without this patch:
> apk add luarocks5.1 lua5.1-dev
> luarocks-5.1 install argparse # fails
# now apply the fix manually:
> apk add wget
> luarocks-5.1 install argparse # succeeds