Revert "Disable link checking for now to speed up builds"

This reverts commit 7d4bb06.

Author: Munter

.travis.yml

@@ -41,7 +41,6 @@ jobs:
       script: bash ./src/scripts/deploy.sh
 
     - stage: post-build
-      if: false # Temporarily shut off link checking to speed up builds
       name: Link check
       script: yarn linkcheck