build(deps): bump alpine from 3.17.3 to 3.18.2 in /docker

Bumps alpine from 3.17.3 to 3.18.2.

---
updated-dependencies:
- dependency-name: alpine
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

docker/Dockerfile

@@ -21,7 +21,7 @@ RUN	go build -ldflags="-X 'github.com/livepeer/stream-tester/model.Version=$vers
 
 RUN	parallel -q go build -ldflags="-X 'github.com/livepeer/stream-tester/model.Version=$version' -X 'github.com/livepeer/stream-tester/model.IProduction=true'" cmd/{}/{}.go ::: testdriver loadtester stream-monitor recordtester
 
-FROM	alpine:3.17.3
+FROM	alpine:3.18.2
 
 RUN	apk add --no-cache ca-certificates ffmpeg