feat(rulesets): add rule to check if the AsyncAPI document is using t…

…he latest version.

docs/reference/asyncapi-rules.md

@@ -174,6 +174,12 @@ info:
     name: MIT
 ```
 
+### asyncapi-latest-version
+
+Checking if the AsyncAPI document is using the latest version.
+
+**Recommended:** Yes
+
 ### asyncapi-message-examples
 
 All `examples` in message object should follow `payload` and `headers` schemas.

packages/rulesets/src/asyncapi/__tests__/asyncapi-latest-version.test.ts

@@ -0,0 +1,27 @@
+import { DiagnosticSeverity } from '@stoplight/types';
+import { latestAsyncApiVersion } from '../functions/asyncApi2DocumentSchema';
+import testRule from './__helpers__/tester';
+
+testRule('asyncapi-latest-version', [
+  {
+    name: 'valid case',
+    document: {
+      asyncapi: latestAsyncApiVersion,
+    },
+    errors: [],
+  },
+
+  {
+    name: 'invalid case',
+    document: {
+      asyncapi: '2.0.0',
+    },
+    errors: [
+      {
+        message: `The latest version is not used. You should update to the "${latestAsyncApiVersion}" version.`,
+        path: ['asyncapi'],
+        severity: DiagnosticSeverity.Information,
+      },
+    ],
+  },
+]);

packages/rulesets/src/asyncapi/functions/asyncApi2DocumentSchema.ts

@@ -12,6 +12,9 @@ import * as asyncAPI2_2_0Schema from '@asyncapi/specs/schemas/2.2.0.json';
 import * as asyncAPI2_3_0Schema from '@asyncapi/specs/schemas/2.3.0.json';
 import * as asyncAPI2_4_0Schema from '@asyncapi/specs/schemas/2.4.0.json';
 
+export const asyncApiSpecVersions = ['2.0.0', '2.1.0', '2.2.0', '2.3.0', '2.4.0'];
+export const latestAsyncApiVersion = asyncApiSpecVersions[asyncApiSpecVersions.length - 1];
+
 function shouldIgnoreError(error: ErrorObject): boolean {
   return (
     // oneOf is a fairly error as we have 2 options to choose from for most of the time.

packages/rulesets/src/asyncapi/index.ts

@@ -10,7 +10,7 @@ import {
 
 import asyncApi2ChannelParameters from './functions/asyncApi2ChannelParameters';
 import asyncApi2ChannelServers from './functions/asyncApi2ChannelServers';
-import asyncApi2DocumentSchema from './functions/asyncApi2DocumentSchema';
+import asyncApi2DocumentSchema, { latestAsyncApiVersion } from './functions/asyncApi2DocumentSchema';
 import asyncApi2MessageExamplesValidation from './functions/asyncApi2MessageExamplesValidation';
 import asyncApi2MessageIdUniqueness from './functions/asyncApi2MessageIdUniqueness';
 import asyncApi2OperationIdUniqueness from './functions/asyncApi2OperationIdUniqueness';
@@ -172,6 +172,22 @@ export default {
         function: truthy,
       },
     },
+    'asyncapi-latest-version': {
+      description: 'Checking if the AsyncAPI document is using the latest version.',
+      message: `The latest version is not used. You should update to the "${latestAsyncApiVersion}" version.`,
+      recommended: true,
+      type: 'style',
+      severity: 'info',
+      given: '$.asyncapi',
+      then: {
+        function: schema,
+        functionOptions: {
+          schema: {
+            const: latestAsyncApiVersion,
+          },
+        },
+      },
+    },
     'asyncapi-message-examples': {
       description: 'Examples of message object should follow by "payload" and "headers" schemas.',
       message: '{{error}}',