[create-next-app]: respecting the user's init.defaultBranch git con… (

vercel#49960)

### What?
This commit makes sure `create-next-app` doesn't ignore user's git configuration (`init.defaultBranch`).
### Why?
Hard coding configurations of a user is annoying (for the user).


Co-authored-by: Steven <229881+styfle@users.noreply.github.com>

packages/create-next-app/helpers/git.ts

@@ -19,6 +19,14 @@ function isInMercurialRepository(): boolean {
   return false
 }
 
+function isDefaultBranchSet(): boolean {
+  try {
+    execSync('git config init.defaultBranch', { stdio: 'ignore' })
+    return true
+  } catch (_) {}
+  return false
+}
+
 export function tryGitInit(root: string): boolean {
   let didInit = false
   try {
@@ -30,7 +38,9 @@ export function tryGitInit(root: string): boolean {
     execSync('git init', { stdio: 'ignore' })
     didInit = true
 
-    execSync('git checkout -b main', { stdio: 'ignore' })
+    if (!isDefaultBranchSet()) {
+      execSync('git checkout -b main', { stdio: 'ignore' })
+    }
 
     execSync('git add -A', { stdio: 'ignore' })
     execSync('git commit -m "Initial commit from Create Next App"', {