Fix watch file

debian/watch

 version=3
 opts=\
-repacksuffix=+ds,\
+repacksuffix=+dfsg,\
 repack,compression=xz,\
-dversionmangle=s/\+(debian|dfsg|ds|deb)(\.\d+)?$//,\
-filenamemangle=s/.*\/v?([\d\.-]+)\.tar\.gz/ruby-markdown-it-html5-embed-$1.tar.gz/ \
+dversionmangle=s/\+(debian|dfsg|ds|deb)(\.\d+)?$// \
  https://gemwatch.debian.net/markdown-it-html5-embed .*/markdown-it-html5-embed-(.*).tar.gz