TBR: roadmap/mojo: update .gitignore to exclude .v23

PresubmitTest: none
Change-Id: I197c12f5332c48f01ec8db8516546522beb568b8
diff --git a/.gitignore b/.gitignore
index 8165887..5f037ee 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,3 +9,5 @@
 .pub
 pubspec.lock
 packages
+
+/.v23