Updating from 2.39.0-dev.3 to 2.39.0-dev.4 (#8168)

Automated Version Bump

packages/devtools_app/lib/devtools.dart

diff --git a/packages/devtools_app/lib/devtools.dart b/packages/devtools_app/lib/devtools.dart
index db1ecfd..aa31586 100644
--- a/packages/devtools_app/lib/devtools.dart
+++ b/packages/devtools_app/lib/devtools.dart
@@ -9,4 +9,4 @@
 // the constant declaration `const version =`.
 // If you change the declaration you must also modify the regex in
 // tools/update_version.dart.
-const version = '2.39.0-dev.3';
+const version = '2.39.0-dev.4';

packages/devtools_app/pubspec.yaml

diff --git a/packages/devtools_app/pubspec.yaml b/packages/devtools_app/pubspec.yaml
index d92c74e..8190011 100644
--- a/packages/devtools_app/pubspec.yaml
+++ b/packages/devtools_app/pubspec.yaml
@@ -4,7 +4,7 @@
 
 # Note: this version should only be updated by running tools/update_version.dart
 # that updates all versions of devtools packages (devtools_app, devtools_test).
-version: 2.39.0-dev.3
+version: 2.39.0-dev.4
 
 repository: https://github.com/flutter/devtools/tree/master/packages/devtools_app