fix: Fix dependencies where build deps were not in dev deps.

Author: treshugart

package.json

@@ -10,7 +10,8 @@
   "devDependencies": {
     "custom-event-polyfill": "^0.2.1",
     "cz-conventional-changelog": "^1.2.0",
-    "semantic-release": "^6.3.2"
+    "semantic-release": "^6.3.2",
+    "skatejs-build": "^12.1.0"
   },
   "scripts": {
     "build": "sk-build",
@@ -32,8 +33,7 @@
   },
   "homepage": "https://github.com/skatejs/dom-diff#readme",
   "dependencies": {
-    "object-assign": "^4.0.1",
-    "skatejs-build": "^12.1.0"
+    "object-assign": "^4.0.1"
   },
   "config": {
     "commitizen": {