fix: 🐛 Downgrade 'undici' to v6 to support Node.js v18 (#74)

## Why?

- Downgraded 'undici' to v6 to support Node.js v18


## Tickets?

-
[PLAT-1900](https://linear.app/fleekxyz/issue/PLAT-1900/yarn-global-installation-of-fleek-platformcli-fails-site-deployment)

## Contribution checklist?

- [x] The commit messages are detailed
- [x] The `build` command runs locally
- [ ] Assets or static content are linked and stored in the project
- [x] You have manually tested
- [ ] You have provided tests

.changeset/modern-clocks-kick.md

@@ -0,0 +1,5 @@
+---
+"@fleek-platform/cli": patch
+---
+
+fix: 🐛 Downgrade 'undici' to v6 to support Node.js v18

package.json

@@ -61,7 +61,7 @@
     "prompts": "^2.4.2",
     "semver": "^7.3.8",
     "ts-node": "10.9.1",
-    "undici": "^7.1.0",
+    "undici": "^6.21.0",
     "unique-names-generator": "^4.7.1",
     "update-notifier-cjs": "^5.1.6"
   },