ci: add workflow_call

Author: raitucarp

.github/workflows/nextjs.yml

@@ -9,6 +9,13 @@ on:
   push:
     branches: ["main"]
 
+  workflow_call:
+    inputs:
+      custom_message:
+        required: false
+        type: string
+        default: "Hello!"
+
   # Allows you to run this workflow manually from the Actions tab
   workflow_dispatch: