[pkg] add build_snap target

Makefile

@@ -91,10 +91,11 @@ build_osx: helper_osx systray_osx bundle_osx pkg_osx
 # -----------------------------------------------------------------------------
 
 build_snap:
-# TODO migrate here the snap folder in bitmask-dev.
-# We should transition pushing *this one* to edge (via launchpad) for some time, and when it's sufficiently tested
-# we can pin this repo as the only source for the snap.
 	echo "[+] building snap..."
+	snapcraft build
+	snapcraft snap
+	mkdir -p dist
+	mv riseup-vpn* dist/
 
 # -----------------------------------------------------------------------------
 # Utils