added product lookup endpoint

app.py

@@ -14,12 +14,12 @@ def get_products():
     return products
 
 @app.get("/products/{productid}")
-def get_product(productid:str):
+def get_product(productid: str):
     with open("products.json", "r") as file:
         products = json.load(file)
 
-	for product in products:
-		if product["productid"] == productid:
-			return product
+    for product in products:
+        if product["productid"] == productid:
+            return product
 
     return {"error": "Product not found"}