travis: update build config import format

Author: lqd

.travis.yml

@@ -3,7 +3,7 @@ dist: xenial
 env:
   RUSTINFRA_DEPLOY_DIR: public
 import:
-  - rust-lang/simpleinfra/travis-configs/static-websites.yml
+  - rust-lang/simpleinfra:travis-configs/static-websites.yml
 install:
   - wget -O /tmp/hugo.deb https://github.com/gohugoio/hugo/releases/download/v0.55.6/hugo_0.55.6_Linux-64bit.deb
   - sudo dpkg -i /tmp/hugo.deb