[create-dapp] Fix path handling on windows (MystenLabs#15319)

## Description 

Describe the changes or additions included in this PR.

## Test Plan 

How did you test the new or updated feature?

---
If your changes are not user-facing and not a breaking change, you can
skip the following section. Otherwise, please indicate what changed, and
then add to the Release Notes section as highlighted during the release
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### Type of Change (Check all that apply)

- [ ] protocol change
- [ ] user-visible impact
- [ ] breaking change for a client SDKs
- [ ] breaking change for FNs (FN binary must upgrade)
- [ ] breaking change for validators or node operators (must upgrade
binaries)
- [ ] breaking change for on-chain data layout
- [ ] necessitate either a data wipe or data migration

### Release notes

---------

Co-authored-by: Jason <[email protected]>

.changeset/calm-deers-rhyme.md

@@ -0,0 +1,5 @@
+---
+'@mysten/create-dapp': patch
+---
+
+Fix handling of paths on windows

sdk/create-dapp/src/index.ts

@@ -111,8 +111,7 @@ async function collectFiles(template: string, dAppName: string) {
 async function writeFiles(files: Array<{ path: string; content: Buffer }>, outDir: string) {
 	for (const file of files) {
 		const filePath = resolve(outDir, file.path);
-		const dirPath = filePath.split('/').slice(0, -1).join('/');
-
+		const dirPath = resolve(filePath, '..');
 		if (!existsSync(dirPath)) {
 			await mkdir(dirPath, { recursive: true });
 		}