[routing-utils] Update routes schema for new property (vercel#6860)

Adds an additional property for the `routes` schema. 

### Related Issues

N/A

### 📋 Checklist

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#### Tests

- [x] The code changed/added as part of this PR has been covered with tests
- [x] All tests pass locally with `yarn test-unit`

#### Code Review

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packages/routing-utils/src/schemas.ts

@@ -150,6 +150,22 @@ export const routesSchema = {
               },
             },
           },
+          middleware: {
+            type: 'object',
+            required: ['id', 'type'],
+            additionalProperties: false,
+            properties: {
+              id: {
+                type: 'string',
+                maxLength: 256,
+              },
+              type: {
+                type: 'string',
+                maxLength: 32,
+                enum: ['v8-worker'],
+              },
+            },
+          },
           has: hasSchema,
         },
       },

packages/routing-utils/src/types.ts

@@ -36,6 +36,10 @@ export type Source = {
     redirect?: Record<string, string>;
     cookie?: string;
   };
+  middleware?: {
+    id: string;
+    type: 'v8-worker';
+  };
 };
 
 export type Handler = {

packages/routing-utils/test/index.spec.js

@@ -58,6 +58,13 @@ describe('normalizeRoutes', () => {
         headers: { 'Cache-Control': 'no-cache' },
         dest: '/blog',
       },
+      {
+        src: '^/.*$',
+        middleware: {
+          id: '1',
+          type: 'v8-worker',
+        },
+      },
       { handle: 'filesystem' },
       { src: '^/(?<slug>[^/]+)$', dest: 'blog?slug=$slug' },
       { handle: 'hit' },

packages/routing-utils/test/merge.spec.js

@@ -487,6 +487,13 @@ test('mergeRoutes ensure beforeFiles comes after redirects (check)', () => {
           check: true,
           override: true,
         },
+        {
+          src: '^/.*$',
+          middleware: {
+            id: '1',
+            type: 'v8-worker',
+          },
+        },
         {
           handle: 'filesystem',
         },
@@ -508,6 +515,13 @@ test('mergeRoutes ensure beforeFiles comes after redirects (check)', () => {
       check: true,
       override: true,
     },
+    {
+      src: '^/.*$',
+      middleware: {
+        id: '1',
+        type: 'v8-worker',
+      },
+    },
     { handle: 'filesystem' },
     { src: '^/404$', dest: '/404', status: 404, check: true },
   ];