fixup! feat(vendir): support extracting HTTP sources

Author: jamietanna

lib/modules/manager/vendir/extract.spec.ts

@@ -32,6 +32,20 @@ describe('modules/manager/vendir/extract', () => {
       expect(result).toBeNull();
     });
 
+    it('returns null for empty `http` key', () => {
+      const nullHttpSource = codeBlock`
+      apiVersion: vendir.k14s.io/v1alpha1
+      kind: Config
+      directories:
+        - path: vendor
+          contents:
+            - path: .
+              http: null
+    `;
+      const result = extractPackageFile(nullHttpSource, 'vendir.yml', {});
+      expect(result).toBeNull();
+    });
+
     it('multiple charts - extracts helm-chart from vendir.yml correctly', () => {
       const result = extractPackageFile(validContents, 'vendir.yml', {
         registryAliases: {