fix archlinux url

supporting-docs/projects/2014-08-12-synapse.md

@@ -16,7 +16,7 @@ Apt repo: [https://matrix.org/packages/debian/](https://matrix.org/packages/debi
 
 Dockerfile from Silvio Fricke: [https://registry.hub.docker.com/u/silviof/docker-matrix/](https://registry.hub.docker.com/u/silviof/docker-matrix/) – also hosted on [https://github.com/matrix-org/docker-matrix](https://github.com/matrix-org/docker-matrix)
 
-ArchLinux package from Ivan Shapovalov: [https://aur.archlinux.org/packages/matrix-synapse](https://aur.archlinux.org/packages/matrix-synapse)
+ArchLinux package from Ivan Shapovalov: [https://www.archlinux.org/packages/community/any/matrix-synapse/](https://www.archlinux.org/packages/community/any/matrix-synapse/)
 
 There is a FreeBSD package on [freshports.org](http://www.freshports.org/net/py-matrix-synapse/).