Update snapcraft build config to Go 1.11
Update snapcraft build config to Go 1.11

See #5115
fedelibre/hugo,mdhender/hugo,anthonyfok/hugo,fedelibre/hugo,mdhender/hugo,mdhender/hugo,gohugoio/hugo,anthonyfok/hugo,fedelibre/hugo,fedelibre/hugo,gohugoio/hugo,gohugoio/hugo,mdhender/hugo,anthonyfok/hugo