Bump dart from `3e60b8f` to `2d73b40` in /auto_submit (#2347)

Bumps dart from `3e60b8f` to `2d73b40`.

---
updated-dependencies:
- dependency-name: dart
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
diff --git a/auto_submit/Dockerfile b/auto_submit/Dockerfile
index f001447..5dbb423 100644
--- a/auto_submit/Dockerfile
+++ b/auto_submit/Dockerfile
@@ -4,7 +4,7 @@
 
 
 # Dart Docker official images can be found here: https://hub.docker.com/_/dart
-FROM dart:beta@sha256:3e60b8fa94aeeb76be28921eaaf46879786d2f3093e387fd3686d5f744f5f063
+FROM dart:beta@sha256:2d73b4052f1c091c6c8ad93a9359a200d2f85bf01521a724cddbc5cc962bfde9
 
 WORKDIR /app