ci(changelog): update formatting and run on change

.github/workflows/changelog.yml

@@ -5,6 +5,7 @@ on:
     branches: [ master ]
     paths:
       - CHANGELOG.md
+      - .github/workflows/changelog.yml
   pull_request:
     branches: [ master ]
     paths:
@@ -17,6 +18,7 @@ jobs:
 
     steps:
     - uses: actions/checkout@v2
+
     - name: Checkout website repository
       uses: actions/checkout@v2
       with:
@@ -24,11 +26,13 @@ jobs:
         repository: pestphp/docs
         path: pestphp-docs
         ref: master
+
     - name: Read CHANGELOG.md
       id: package
       uses: juliangruber/read-file-action@v1
       with:
         path: ./CHANGELOG.md
+
     - name: Add file headers
       uses: DamianReeves/write-file-action@v1.0
       with:
@@ -44,8 +48,10 @@ jobs:
 
           Next section: [Upgrade Guide →](/docs/upgrade-guide)
         write-mode: overwrite
+
     - name: Copy CHANGELOG to website repository
       run: cp CHANGELOG.md pestphp-docs/changelog.md
+
     - name: Create Pull Request
       uses: peter-evans/create-pull-request@v2
       with: