chore: fix commitlint config (#592)

Add [plugin](https://github.com/watson/commitlint-config-squash-pr) for allowing longer squashed messages (since a squash adds the PR number) and disable the annoying scope case rule so that for instance `feat(Button)` is allowed (same as our internal config).

package.json

@@ -48,8 +48,10 @@
   },
   "commitlint": {
     "extends": [
+      "squash-pr",
       "@commitlint/config-conventional"
-    ]
+    ],
+    "rules": { "scope-case": [0] }
   },
   "lint-staged": {
     "*.{js,jsx}": [
@@ -96,6 +98,7 @@
     "babel-plugin-lodash": "3.3.4",
     "codecov": "3.2.0",
     "commitizen": "3.0.7",
+    "commitlint-config-squash-pr": "1.0.1",
     "cross-env": "5.2.0",
     "cz-conventional-changelog": "2.1.0",
     "enzyme": "3.9.0",

yarn.lock

@@ -2832,6 +2832,11 @@ commitizen@3.0.7:
     strip-bom "3.0.0"
     strip-json-comments "2.0.1"
 
+commitlint-config-squash-pr@1.0.1:
+  version "1.0.1"
+  resolved "https://registry.npmjs.org/commitlint-config-squash-pr/-/commitlint-config-squash-pr-1.0.1.tgz#8bd288f63a5b4fa1e845cf88491aba2f1c7a708c"
+  integrity sha512-L1ajC7gJT1QY3+Rxf982bMl1utQkBpk5sL+5pU/zIjimCUedi+BpMuHUyDjAtxP2xnqwc7Nvx3ojPh56Askm6A==
+
 common-dir@^2.0.2:
   version "2.0.2"
   resolved "https://registry.npmjs.org/common-dir/-/common-dir-2.0.2.tgz#cfea16f48564a0ecbb088065fad029047f469dc1"