core: Add wip as a valid commit type (commitlint)

.commitlintrc.yaml

@@ -2,7 +2,7 @@ extends:
   - '@commitlint/config-conventional'
 help: |
   **Possible types**:
-  `ci`:       Changes to our CI configuration files and scripts (example scopes: Travis, Circle, BrowserStack, SauceLabs)
+  `ci`:       Changes to our CI configuration files and scripts (example scopes: Travis, Circle, BrowserStack, SauceLabs).
   `core`:     Change build process, tooling or dependencies.
   `docs`:     Adds or alters documentation.
   `feat`:     Adds a new feature.
@@ -12,6 +12,7 @@ help: |
   `revert`:   Changes that reverting other changes
   `style`:    Improves formatting, white-space.
   `test`:     Adds or modifies tests.
+  `wip`:      Work in progress (temporary commits, which will eventually be rebased or otherwise removed).
 rules:
   body-max-line-length: [1, 'always', 72]
   header-max-length: [1, 'always', 50]
@@ -29,3 +30,4 @@ rules:
       - revert
       - style
       - test
+      - wip