update v2 spec + python lint

Author: aayushijain21

specs/x402-specification-v2.md

@@ -78,7 +78,10 @@ When a resource server requires payment, it responds with a payment required sig
   "resource": {
     "url": "https://api.example.com/premium-data",
     "description": "Access to premium market data",
-    "mimeType": "application/json"
+    "mimeType": "application/json",
+    "serviceName": "Example Market Data",
+    "tags": ["market-data", "finance"],
+    "iconUrl": "https://api.example.com/icon.png"
   },
   "accepts": [
     {
@@ -124,11 +127,14 @@ Each `PaymentRequirements` object in the `accepts` array contains:
 
 The `ResourceInfo` object contains:
 
-| Field Name    | Type     | Required | Description                                |
-| ------------- | -------- | -------- | ------------------------------------------ |
-| `url`         | `string` | Required | URL of the protected resource              |
-| `description` | `string` | Optional | Human-readable description of the resource |
-| `mimeType`    | `string` | Optional | MIME type of the expected response         |
+| Field Name      | Type            | Required | Description                                                                                                          |
+| --------------- | --------------- | -------- | -------------------------------------------------------------------------------------------------------------------- |
+| `url`           | `string`        | Required | URL of the protected resource                                                                                        |
+| `description`   | `string`        | Optional | Human-readable description of the resource                                                                           |
+| `mimeType`      | `string`        | Optional | MIME type of the expected response                                                                                   |
+| `serviceName`   | `string`        | Optional | Human-readable name of the service hosting the resource. Printable ASCII, max 32 characters.                         |
+| `tags`          | `array[string]` | Optional | Topical tags for the service, used for discovery filtering. Max 5 entries; each printable ASCII, max 32 characters.  |
+| `iconUrl`       | `string`        | Optional | Absolute `https`/`http` URL to an icon representing the service. Max 2048 characters.                               |
 
 The `Extensions` object is a key-value map where each key is an extension identifier and each value follows a standardized structure: