Updated the Vercel PAT setup instructions.
The original instructions don't say to enable `repo` permissions on the Personal Access Token. Without these permissions, the widget was not able to count the `total commits` on my private repos. I updated the instructions to specifically mention enabling the `repo` permission on the PAT.
I tested this using my own Vercel instance and can confirm the `repo` permission is needed.
This fix has been mentioned here: https://github.com/anuraghazra/github-readme-stats/issues/1275#issuecomment-929887319
