snapcraft.yaml: Bump version to 0.18-DEV
snapcraft.yaml: Bump version to 0.18-DEV

and set grade to "devel" for the new development series.

digitalcraftsman/hugo,mdhender/hugo,gohugoio/hugo,anthonyfok/hugo,jygastaud/hugo,Zenithar/hugo,mdhender/hugo,mdhender/hugo,mayah/hugo,digitalcraftsman/hugo,fedelibre/hugo,tubo028/hugo,mitchchn/hugo,Zenithar/hugo,mdhender/hugo,MarkDBlackwell/hugo,MarkDBlackwell/hugo,anthonyfok/hugo,tubo028/hugo,bogem/hugo,fedelibre/hugo,gohugoio/hugo,jygastaud/hugo,anthonyfok/hugo,mayah/hugo,fedelibre/hugo,gohugoio/hugo,mitchchn/hugo,fedelibre/hugo,bogem/hugo