feat: update .env variable table formatting for clarity in Docker Hub credentials section

Author: abdibekbolot

docs/miner/workflow/4.submit-commit.md

@@ -85,10 +85,10 @@ Your miner needs Docker Hub credentials to pull your private images during valid
 
 These values go into your `.env` file in the next step:
 
-| `.env` variable | Value |
-|---|---|
-| `DOCKER_HUB_USERNAME` | Your Docker Hub username |
-| `DOCKER_HUB_PAT` | The Read-only PAT you generated |
+| `.env` variable       | Value                           |
+| --------------------- | ------------------------------- |
+| `DOCKER_HUB_USERNAME` | Your Docker Hub username        |
+| `DOCKER_HUB_PAT`      | The Read-only PAT you generated |
 
 !!! danger "Never commit your PAT"
     Add `.env` to your `.gitignore`. If you accidentally expose a PAT, revoke it immediately from the [security settings page](https://hub.docker.com/settings/security) and generate a new one.