Move scalafmt to separate workflow

Author: stringbean

.github/workflows/ci.yml

@@ -23,21 +23,4 @@ jobs:
       - name: Run tests
         uses: lokkju/github-action-sbt@master
         with:
-          commands: test scripted headerCheck scapegoat
-
-  scalafmt:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v2
-      # only fetch the head commits of our branch & mainline
-      # loosely based on https://github.com/actions/checkout/issues/329#issuecomment-717076567
-      - name: Checkout branch history
-        run: |
-          git remote set-branches origin "${{github.base_ref}}" "${{github.head_ref}}"
-          git fetch --depth 1
-          git checkout "${{github.head_ref}}"
-
-      - name: Run scalafmt
-        uses: stringbean/scalafmt-action@v2.0.0-beta
-        with:
-          compare-branch: master
+          commands: test scripted headerCheck scapegoat

.github/workflows/scalafmt-lint.yml

@@ -0,0 +1,27 @@
+name: Scalafmt lint
+
+on:
+  pull_request:
+    paths:
+      - 'src/main/code/**'
+      - 'src/test/code/**'
+      - 'build.sbt'
+      - 'project/*.scala'
+
+jobs:
+  lint:
+    name: Scalafmt
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+
+      # only fetch the head commits of our branch & mainline
+      # loosely based on https://github.com/actions/checkout/issues/329#issuecomment-717076567
+      - name: Checkout branches
+        run: |
+          git remote set-branches origin "${{github.base_ref}}" "${{github.head_ref}}"
+          git fetch --depth 1
+          git checkout "${{github.head_ref}}"
+      - uses: stringbean/scalafmt-action@v2.0.0-beta
+        with:
+          compare-branch: master