feat(bazel): set sourceUrl for Bazel modules (#33840)

Co-authored-by: Michael Kriese <michael.kriese@gmx.de>

lib/modules/datasource/bazel/__fixtures__/metadata-no-yanked-versions.json

 {
+    "homepage": "https://github.com/foo/bar",
     "versions": [
         "0.14.8",
         "0.14.9",

lib/modules/datasource/bazel/index.spec.ts

@@ -58,6 +58,7 @@ describe('modules/datasource/bazel/index', () => {
           { version: '0.15.0' },
           { version: '0.16.0' },
         ],
+        sourceUrl: 'https://github.com/foo/bar',
       });
     });
 

lib/modules/datasource/bazel/index.ts

@@ -57,6 +57,9 @@ export class BazelDatasource extends Datasource {
           }
           return release;
         });
+      if (metadata.homepage) {
+        result.homepage = metadata.homepage;
+      }
     } catch (err) {
       // istanbul ignore else: not testable with nock
       if (err instanceof HttpError) {

lib/modules/datasource/bazel/schema.ts

 import { z } from 'zod';
 
 export const BazelModuleMetadata = z.object({
+  homepage: z.string().optional().nullable(),
   versions: z.array(z.string()),
   yanked_versions: z.record(z.string(), z.string()),
 });