Merge pull request docker-library#12868 from sortie/pr-update-dart

Update dart

Author: yosifkit

library/dart

@@ -1,12 +1,12 @@
 Maintainers: Alexander Thomas <[email protected]> (@athomas), Tony Pujals <[email protected]> (@subfuzion)
 GitRepo: https://github.com/dart-lang/dart-docker.git
 GitFetch: refs/heads/main
-GitCommit: 4287f4249cc45f8df11107d7b9dcc4e6618644e5
+GitCommit: b73710e1fd5fa709206bcd5878cb9e213012d57a
 
 Tags: 2.17.6-sdk, 2.17-sdk, 2-sdk, stable-sdk, sdk, 2.17.6, 2.17, 2, stable, latest
 Architectures: amd64, arm32v7, arm64v8
 Directory: stable/bullseye
 
-Tags: 2.18.0-271.2.beta-sdk, beta-sdk, 2.18.0-271.2.beta, beta
+Tags: 2.18.0-271.4.beta-sdk, beta-sdk, 2.18.0-271.4.beta, beta
 Architectures: amd64, arm32v7, arm64v8
 Directory: beta/bullseye