Update Grafana files

Author: ebattat

benchmark_runner/grafana/perf/dashboard.json

@@ -1588,6 +1588,10 @@
                            "index": 387,
                            "text": "4.17.5-6"
                         },
+                        "418010": {
+                           "index": 393,
+                           "text": "4.18.0-rc.10"
+                        },
                         "41803": {
                            "index": 372,
                            "text": "4.18.0-rc.3"
@@ -1620,6 +1624,10 @@
                            "index": 389,
                            "text": "4.18.0-825"
                         },
+                        "4180836": {
+                           "index": 394,
+                           "text": "4.18.0-836"
+                        },
                         "4814": {
                            "index": 6,
                            "text": "4.8.14"