Increase number of allowed requests per log parser

The default limit of requests accepted by Loki from a single host was
set to 10000, which is not enough for a large Gerrit instance to push
all httpd/sshd-logs to Loki.

Change-Id: I94cb56e00102170ae4ed10e90123a8885e3aad00
diff --git a/charts/loki/loki.yaml b/charts/loki/loki.yaml
index 62645bb..51f26f0 100644
--- a/charts/loki/loki.yaml
+++ b/charts/loki/loki.yaml
@@ -66,6 +66,7 @@
       #     consistentreads: true
   limits_config:
     enforce_metric_name: false
+    max_streams_per_user: 1000000
     reject_old_samples: true
     reject_old_samples_max_age: 168h
   schema_config: