fix secret name

Author: bruecksen

.github/workflows/django.yml

@@ -32,7 +32,7 @@ jobs:
       env:
         SSH_PRIVATE_KEY: ${{ secrets.SSH_KEY }}
         SSH_HOST: ${{ secrets.SSH_HOST }}
-        SSH_USERNAME: ${{ secrets.SSH_USERNAME }}
+        SSH_USERNAME: ${{ secrets.SSH_USER }}
       run: |
         echo "$SSH_PRIVATE_KEY" | tr -d '\r' | ssh-add - > /dev/null
         ssh-keyscan -H "$SSH_HOST" >> ~/.ssh/known_hosts