feat(deps): adds sortablejs and @types/sortablejs as peer dependencies

BREAKING CHANGE: Users want to use their own versions of sortablejs, so we'll allow it.

ref #175, closes #148

Author: waynevanson

package.json

@@ -41,12 +41,12 @@
   },
   "peerDependencies": {
     "react": "^16.9.0",
-    "react-dom": "^16.9.0"
+    "react-dom": "^16.9.0",
+    "sortablejs": "^1.10.0",
+    "@types/sortablejs": "^1.10.0"
   },
   "dependencies": {
-    "@types/sortablejs": "^1.10.0",
     "classnames": "^2.2.6",
-    "sortablejs": "1.10.1",
     "tiny-invariant": "^1.0.6"
   },
   "devDependencies": {