undo docs addon upgrade as it breaks embroider tests

Author: nlfurniss

package.json

@@ -60,7 +60,7 @@
     "babel-eslint": "^10.1.0",
     "codeclimate-test-reporter": "^0.5.0",
     "ember-cli": "^3.25.0",
-    "ember-cli-addon-docs": "^3.0.0",
+    "ember-cli-addon-docs": "^0.10.0",
     "ember-cli-addon-docs-yuidoc": "^0.2.4",
     "ember-cli-dependency-checker": "^3.0.0",
     "ember-cli-deploy": "^1.0.2",