Add SwiftFormat linting to CI workflow (#55)

Signed-off-by: Gray Campbell <12163070+graycampbell@users.noreply.github.com>

Author: graycampbell

.github/workflows/ci.yml

@@ -23,7 +23,13 @@ jobs:
         with:
           xcode-version: latest
 
-      - name: Install dependencies
+      - name: Install Brewfile dependencies
+        run: brew bundle install
+
+      - name: Run SwiftFormat in lint mode
+        run: swiftformat --lint .
+
+      - name: Install package dependencies
         run: swift package resolve
 
       - name: Build the package