Use the correct username for Grafana

Author: Matt Pryor

slurm-infra.yml

@@ -146,7 +146,7 @@
         zenith_proxy_client_auth_params: {}
         zenith_proxy_mitm_enabled: yes
         zenith_proxy_mitm_auth_inject: basic
-        zenith_proxy_mitm_auth_basic_username: admin
+        zenith_proxy_mitm_auth_basic_username: grafana
         zenith_proxy_mitm_auth_basic_password: "{{ vault_grafana_admin_password }}"
       when: zenith_subdomain_monitoring is defined