travis: Increase timeout to 30000 for mage -v check
travis: Increase timeout to 30000 for mage -v check

The default timeout of 15000 millisecond is too short
for go test -race on arm64.

See golang/go#35308

anthonyfok/hugo,gohugoio/hugo,gohugoio/hugo,anthonyfok/hugo,gohugoio/hugo,anthonyfok/hugo