Install bsdoc independently from rest of the package

Author: yawaramin

.travis.yml

@@ -5,6 +5,8 @@ on:
   branch: master
 os: osx
 osx_image: xcode12
+before_install:
+  - npm install [email protected]
 
 deploy:
   - provider: npm

package.json

@@ -26,10 +26,12 @@
   "author": "chenglou",
   "license": "MIT",
   "devDependencies": {
-    "bs-platform": "^7.1.0",
-    "bsdoc": "6.0.4-alpha"
+    "bs-platform": "^7.1.0"
   },
   "dependencies": {
     "bs-fetch": "^0.6.2"
+  },
+  "peerDependencies": {
+    "bsdoc": "^6.0.4-alpha"
   }
 }