Prevent disabling all checks

Prevent users from disabling both the license and vulnerability check by
checking if both are set to `false` and throwing if that's the case.

__tests__/config.test.ts

@@ -215,6 +215,14 @@ test('it parses the vulnerability-check input', async () => {
   expect(options.vulnerability_check).toEqual(true)
 })
 
+test('it is not impossible to disable both checks', async () => {
+  setInput('license-check', 'false')
+  setInput('vulnerability-check', 'false')
+  expect(() => {
+    readConfig()
+  }).toThrow("Can't disable both license-check and vulnerability-check")
+})
+
 describe('licenses that are not valid SPDX licenses', () => {
   beforeAll(() => {
     jest.spyOn(Utils, 'isSPDXValid').mockReturnValue(false)

src/config.ts

@@ -90,6 +90,9 @@ export function readInlineConfig(): ConfigurationOptions {
     .boolean()
     .default(true)
     .parse(getOptionalBoolean('vulnerability-check'))
+  if (license_check === false && vulnerability_check === false) {
+    throw new Error("Can't disable both license-check and vulnerability-check")
+  }
 
   const base_ref = getOptionalInput('base-ref')
   const head_ref = getOptionalInput('head-ref')