Mention issue number in commit

Author: robvanderleek

src/github.js

@@ -211,7 +211,8 @@ async function createPR (app, ctx, config, username, branchName) {
   try {
     const commitSha = await getBranchHeadSha(ctx, branchName)
     const treeSha = await getCommitTreeSha(ctx, commitSha)
-    const emptyCommitSha = await createCommit(ctx, commitSha, treeSha, username, `Create ${draftText}PR`)
+    const emptyCommitSha = await createCommit(ctx, commitSha, treeSha, username,
+      `Create ${draftText}PR for #${issueNumber}`)
     await updateReference(ctx, branchName, emptyCommitSha)
     await ctx.octokit.pulls.create(
       { owner, repo, head: branchName, base, title, body: `closes #${issueNumber}`, draft: draft })

tests/github.test.js

@@ -219,7 +219,7 @@ test('create (draft) PR', async () => {
     body: 'closes #1',
     title: 'Hello world'
   })
-  expect(capturedCommitMessage).toBe('Create PR')
+  expect(capturedCommitMessage).toBe('Create PR for #1')
   await github.createPR({ log: () => { } }, ctx, { silent: false, openDraftPR: true },
     'robvanderleek', 'issue-1')
   expect(createPR).toHaveBeenCalledWith({
@@ -231,5 +231,5 @@ test('create (draft) PR', async () => {
     body: 'closes #1',
     title: 'Hello world'
   })
-  expect(capturedCommitMessage).toBe('Create draft PR')
+  expect(capturedCommitMessage).toBe('Create draft PR for #1')
 })