test(scripts): fix failing changelog unit test (#1626)

The markdown changelog is generated with a date, updated test harness to
use Sinon's fake timers feature to lock the clock to a specific date so
our assertion doesn't have to change every day.

bin/test/conventional-changelog.test.js

@@ -52,7 +52,7 @@ const exampleCommit = {
   }
 }
 
-const exampleMarkdown = `### v1.0.0 (2023-05-05)
+const exampleMarkdown = `### v1.0.0 (2020-04-03)
 
 #### ⚠ BREAKING CHANGES
 
@@ -68,12 +68,14 @@ const exampleMarkdown = `### v1.0.0 (2023-05-05)
 tap.test('Conventional Changelog Class', (testHarness) => {
   testHarness.autoend()
 
+  let clock
   let MockGithubSdk
   let mockGetPrByCommit
   let mockGitLog
   let ConventionalChangelog
 
   testHarness.beforeEach(() => {
+    clock = sinon.useFakeTimers(new Date('2020-04-03'))
     mockGetPrByCommit = sinon.stub()
     MockGithubSdk = sinon.stub().returns({
       getPullRequestByCommit: mockGetPrByCommit
@@ -87,6 +89,10 @@ tap.test('Conventional Changelog Class', (testHarness) => {
     })
   })
 
+  testHarness.afterEach(() => {
+    clock.restore()
+  })
+
   testHarness.test('rankedGroupSort - should order a list of groupings based on rank', (t) => {
     const changelog = new ConventionalChangelog({ newVersion: '1.0.0', previousVersion: '0.9.0' })