chore(package): add semantic-release as a dev dependency

Since we use `--ignore-engines` when installing, this is now ok

Author: SimenB

.travis.yml

@@ -20,9 +20,7 @@ jobs:
   - stage: release
     node_js: 8
     os: linux
-    after_success:
-    - yarn add -D [email protected]
-    - yarn semantic-release
+    after_success: yarn semantic-release
 cache:
   yarn: true
 branches:

package.json

@@ -29,7 +29,8 @@
     "husky": "^0.14.3",
     "jest": "^22.0.4",
     "lint-staged": "^6.0.0",
-    "prettier": "^1.8.1"
+    "prettier": "^1.8.1",
+    "semantic-release": "^11.0.2"
   },
   "prettier": {
     "singleQuote": true,