Update invalid live demo link (#1951)

Dominik Strässle · phanan · commit 80bcee01284c · 2019-01-21T12:14:56.000+01:00
The link to the live demo is not up-to-date. I've updated it to the same one as noted in [vue-hackernews-2.0](https://github.com/vuejs/vue-hackernews-2.0/blob/master/README.md)
diff --git a/src/v2/examples/hackernews.md b/src/v2/examples/hackernews.md
@@ -14,7 +14,7 @@ order: 12
 </div>
 {% endraw %}
 
-> [Live Demo](https://vue-hn.now.sh/)
+> [Live Demo](https://vue-hn.herokuapp.com/)
 > Note: the demo may need some spin up time if nobody has accessed it for a certain period.
 >
 > [[Source](https://github.com/vuejs/vue-hackernews-2.0)]

Original file line number	Diff line number	Diff line change
`@@ -14,7 +14,7 @@ order: 12`
`14`	`14`	`</div>`
`15`	`15`	`{% endraw %}`
`16`	`16`
`17`		`-> [Live Demo](https://vue-hn.now.sh/)`
	`17`	`+> [Live Demo](https://vue-hn.herokuapp.com/)`
`18`	`18`	`> Note: the demo may need some spin up time if nobody has accessed it for a certain period.`
`19`	`19`	`>`
`20`	`20`	`> [[Source](https://github.com/vuejs/vue-hackernews-2.0)]`