fix syntax error

Author: SoftwareRat

.github/workflows/build.yml

@@ -49,8 +49,9 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        config: [${{ inputs.config || 'pppwn_defconfig' }}]
-        architecture: [${{ inputs.architecture || 'x86_64' }}]
+        include:
+          - config: ${{ inputs.config || 'pppwn_defconfig' }}
+            architecture: ${{ inputs.architecture || 'x86_64' }}
 
     steps:
     - name: Checkout repository