[ci] Update Flutter version for release (#10425)

When updating the repo for the 3.38 release, I missed the step of updating the release script (it's in the documented steps already, I just missed that line this time). This is causing a `release` failure for packages that require 3.38.

Uses 3.38.1 rather than 3.38.0 because of the Dart version mistake in 3.38.0.

Author: stuartmorgan-g

.github/workflows/release.yml

@@ -31,7 +31,7 @@ jobs:
       # the change if it doesn't.
       run: |
         cd $HOME
-        git clone https://github.com/flutter/flutter.git --depth 1 -b 3.35.0 _flutter
+        git clone https://github.com/flutter/flutter.git --depth 1 -b 3.38.1 _flutter
         echo "$HOME/_flutter/bin" >> $GITHUB_PATH
         cd $GITHUB_WORKSPACE
     # Checks out a copy of the repo.

script/tool/lib/src/common/file_filters.dart

@@ -22,6 +22,7 @@ bool isRepoLevelNonCodeImpactingFile(String path) {
         '.github/dependabot.yml',
         '.github/labeler.yml',
         '.github/post_merge_labeler.yml',
+        '.github/workflows/release.yml',
         '.github/workflows/pull_request_label.yml',
       ].contains(path) ||
       // This directory only affects automated code reviews, so cannot affect