add .bazelversion to .gitignore file

PiperOrigin-RevId: 259299473
diff --git a/.gitignore b/.gitignore
index cfb42f8..203884b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -19,3 +19,5 @@
 # Ignore jekyll build output.
 /production
 /.sass-cache
+# Bazelisk version file
+.bazelversion
\ No newline at end of file