Made sure travis caches mdbook-linkcheck's cache file

Michael-F-Bryan · mark-i-m · commit 1952189e86da · 2019-09-05T17:03:24.000-05:00
diff --git a/.travis.yml b/.travis.yml
@@ -3,6 +3,8 @@ rust:
 - nightly
 cache:
 - cargo
+- directories:
+  - book/linkcheck/
 before_install:
 - shopt -s globstar
 - MAX_LINE_LENGTH=100 bash ci/check_line_lengths.sh src/**/*.md
