Update Grafana files

Author: ebattat

benchmark_runner/grafana/perf/dashboard.json

@@ -2206,6 +2206,10 @@
                            "index": 524,
                            "text": "4.21.0-83"
                         },
+                        "4211": {
+                           "index": 537,
+                           "text": "4.21.1"
+                        },
                         "4814": {
                            "index": 6,
                            "text": "4.8.14"