fix: link to Vercel adaptor README (#2537)

Link to the full guide is broken.

Only thing that seems to be weird was that the link `https://github.com/BuilderIO/qwik/blob/main/starters/adaptors/Vercel-edge/README.md` has `Vercel` in the URL with a capital `V`.
fixing to lowercase should do the job.

Author: hamatoyogi

packages/docs/src/routes/integrations/deployments/vercel-edge/index.mdx

@@ -38,7 +38,7 @@ To build the application for production, use the `build` command, this command w
 npm run build
 ```
 
-[Read the full guide here](https://github.com/BuilderIO/qwik/blob/main/starters/adaptors/Vercel-edge/README.md)
+[Read the full guide here](https://github.com/BuilderIO/qwik/blob/main/starters/adaptors/vercel-edge/README.md)
 
 ## Dev deploy