chore(deps): update otel/opentelemetry-collector-contrib docker tag to v0.121.0 (open-telemetry#6885)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

examples/otel-collector/docker-compose.yaml

@@ -3,7 +3,7 @@
 
 services:
  otel-collector:
- image: otel/opentelemetry-collector-contrib:0.120.0
+ image: otel/opentelemetry-collector-contrib:0.121.0
  command: ["--config=/etc/otel-collector.yaml"]
  volumes:
  - ./otel-collector.yaml:/etc/otel-collector.yaml