Fix Github Pages path.

ehuss · mark-i-m · commit b9bc44dc5c89 · 2018-02-17T22:46:40.000-06:00
The newer version of mdBook uses a different path for the html output.
diff --git a/.travis.yml b/.travis.yml
@@ -16,6 +16,6 @@ deploy:
   provider: pages
   skip-cleanup: true
   github-token: $GITHUB_TOKEN
-  local-dir: book
+  local-dir: book/html
   on:
     branch: master
