added filter option & tests

__test__/input-helper.test.ts

@@ -79,6 +79,7 @@ describe('input-helper tests', () => {
     expect(settings.clean).toBe(true)
     expect(settings.commit).toBeTruthy()
     expect(settings.commit).toBe('1234567890123456789012345678901234567890')
+    expect(settings.filter).toBe(undefined)
     expect(settings.sparseCheckout).toBe(undefined)
     expect(settings.sparseCheckoutConeMode).toBe(true)
     expect(settings.fetchDepth).toBe(1)