ci: trigger on PR (#61)

* ci: trigger ci on PR

* ci: trigger only on PR

* ci: fix lint staged diff arguments

* ci: run on PR against all branches

.github/workflows/ci.yml

@@ -1,6 +1,6 @@
 name: CI
 on:
-  push:
+  pull_request:
     branches:
       - "**"
 jobs:
@@ -25,7 +25,7 @@ jobs:
         if: steps.cache.outputs.cache-hit != 'true'
         run: npm ci
       - name: Run pre-commit hooks
-        run: npx lint-staged --diff=origin/${{ github.event.repository.default_branch }}...origin/${{ github.ref_name }}
+        run: npx lint-staged --diff=origin/${{ github.base_ref }}...origin/${{ github.head_ref }}
   test:
     needs: pre-commit
     strategy: