Upgrade hallmark devDependency from ^1.0.0 to ^2.0.0 (#672)

* Upgrade hallmark devDependency from ^1.0.0 to ^2.0.0
* Add `git fetch --tags` to Travis for historical tags

Author: greenkeeper[bot]

.travis.yml

@@ -18,6 +18,8 @@ matrix:
       hosts:
         - airtap.local
 
+before_script: git fetch --tags
+
 script:
   - DEBUG=airtap:* npm run $CMD
 

package.json

@@ -31,7 +31,7 @@
     "delayed": "^2.0.0",
     "dependency-check": "^3.3.0",
     "encoding-down": "^6.0.0",
-    "hallmark": "^1.0.0",
+    "hallmark": "^2.0.0",
     "level-community": "^3.0.0",
     "memdown": "^5.0.0",
     "nyc": "^14.0.0",