grafana: filter http requests total for aur on job

http_requests_total  contains requests from debuginfo.al.org host
as well as from aur.al.org so filter them on job 'aurweb'

Signed-off-by: Leonidas Spyropoulos <artafinde@archlinux.org>

roles/grafana/files/dashboards/aur.json

@@ -105,7 +105,7 @@
             "uid": "PBFA97CFB590B2093"
           },
           "exemplar": true,
-          "expr": "rate(http_requests_total[5m])",
+          "expr": "rate(http_requests_total{job=\"aurweb\"}[5m])",
           "interval": "",
           "legendFormat": "{{ path }} {{ status }}",
           "refId": "A"