Merge pull request #2109 from loft-sh/v6-docs-getting-started

docs: add instructions for upgrading to v6-beta.0

Author: LukasGentele

docs/pages/getting-started/installation.mdx

@@ -6,3 +6,14 @@ sidebar_label: 1. Download DevSpace
 import InstallFragment from '../_partials/install-cli.mdx';
 
 <InstallFragment/>
+
+## Upgrade To DevSpace v6
+Since you are viewing the docs for DevSpace v6, make sure to upgrade to DevSpace v6 (currently in beta):
+
+```bash
+devspace upgrade --version=v6.0.0-beta.0
+```
+
+:::warning Upgrade Required
+The rest of this documentation refers to DevSpace v6, so make sure to upgrade. You can always downgrade to v5 using this command: `devspace upgrade --version=v5.18.5`
+:::