(fix) Move changelog job to it's own workflow (rojo-rbx#720)

- moved the job to its own workflow file
- changed the label to `skip changelog`

.github/workflows/changelog.yml

@@ -0,0 +1,23 @@
+name: Changelog Check
+
+on:
+  pull_request:
+    types: [assigned, opened, synchronize, reopened, labeled, unlabeled]
+    branches:
+      - master
+
+jobs:
+  build:
+    name: Check Actions
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+
+    - name: Changelog check
+      uses: Zomzog/changelog-checker@v1.3.0
+      with:
+        fileName: CHANGELOG.md 
+        noChangelogLabel: skip changelog
+        checkNotification: Simple
+      env:
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/ci.yml

@@ -68,18 +68,3 @@ jobs:
     - name: Clippy
       run: cargo clippy
 
-  Changelog:
-    name: Changelog Check
-    runs-on: ubuntu-latest
-    steps:
-    - uses: actions/checkout@v3
-    - name: Changelog check
-
-      uses: Zomzog/changelog-checker@v1.3.0
-      with:
-        fileName: CHANGELOG.md 
-        noChangelogLabel: no changelog
-        checkNotification: Simple
-      env:
-        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-