chore(deps): update grafana/k6 docker digest to e66db15 (#2494)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| grafana/k6 | digest | `5221b62` → `e66db15` |

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examples/example-exemplars-tail-sampling/docker-compose.yaml

@@ -68,7 +68,7 @@ services:
       - ./config/grafana-dashboards.yaml:/etc/grafana/provisioning/dashboards/grafana-dashboards.yaml
       - ./config/grafana-example-dashboard.json:/etc/grafana/example-dashboard.json
   k6:
-    image: grafana/k6@sha256:5221b620a4f874faff6e32ba597aa667c058391fe4898b1c6f6377f062c6cdec
+    image: grafana/k6@sha256:e66db15b860113878fa74670e31f5e274830b7b6e42c8bff28b2f2d86a257603
     network_mode: host
     volumes:
       - ./config/k6-script.js:/k6-script.js