fix(config): do not massage lockFileMaintenance (#11522)

lib/config/__snapshots__/massage.spec.ts.snap

 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`config/massage massageConfig does not massage lockFileMaintenance 1`] = `
+Object {
+  "packageRules": Array [
+    Object {
+      "lockFileMaintenance": Object {
+        "enabled": true,
+      },
+      "matchBaseBranches": Array [
+        "release/ft10/1.9.x",
+      ],
+      "matchManagers": Array [
+        "helmv3",
+      ],
+      "schedule": Array [
+        "at any time",
+      ],
+    },
+  ],
+}
+`;
+
 exports[`config/massage massageConfig massages packageRules matchUpdateTypes 1`] = `
 Object {
   "packageRules": Array [

lib/config/massage.spec.ts

@@ -42,5 +42,20 @@ describe('config/massage', () => {
       expect(res).toMatchSnapshot();
       expect(res.packageRules).toHaveLength(3);
     });
+    it('does not massage lockFileMaintenance', () => {
+      const config: RenovateConfig = {
+        packageRules: [
+          {
+            matchManagers: ['helmv3'],
+            matchBaseBranches: ['release/ft10/1.9.x'],
+            lockFileMaintenance: { enabled: true },
+            schedule: ['at any time'],
+          },
+        ],
+      };
+      const res = massage.massageConfig(config);
+      expect(res).toMatchSnapshot();
+      expect(res.packageRules).toHaveLength(1);
+    });
   });
 });

lib/config/massage.ts

@@ -47,7 +47,6 @@ export function massageConfig(config: RenovateConfig): RenovateConfig {
       'patch',
       'pin',
       'digest',
-      'lockFileMaintenance',
       'rollback',
     ];
     for (const rule of massagedConfig.packageRules) {