Update Windows template version (#58189)

PR #57749 included changes to the way the project interacts with the
build process (e.g., bundling the necessary library), so should have
incremented the template version to trigger the messaging to developers.
diff --git a/packages/flutter_tools/templates/app/windows.tmpl/flutter/.template_version b/packages/flutter_tools/templates/app/windows.tmpl/flutter/.template_version
index 0cfbf08..00750ed 100644
--- a/packages/flutter_tools/templates/app/windows.tmpl/flutter/.template_version
+++ b/packages/flutter_tools/templates/app/windows.tmpl/flutter/.template_version
@@ -1 +1 @@
-2
+3