chore(deps): update grafana/k6 docker digest to a7c79af (#1763)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| grafana/k6 | digest | `16bc234` → `a7c79af` |

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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@sha256:16bc2347c323b1155a200d6fe9c2b801a570b6e0e647203cf382a083782b904f
+    image: grafana/k6@sha256:a7c79af2b374c9a3afa8b0fae9ec2899277d066612029b7b0fcd2fcb724ba86f
     network_mode: host
     volumes:
       - ./config/k6-script.js:/k6-script.js