Add -Xss2m maven option to .mvn/jvm.config

Change-Id: I38ceda1241e78a335a41ebaf629184eb26d9996a
diff --git a/.gitignore b/.gitignore
index da31729..252935e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,7 @@
 .*
 !/.gitignore
 !/.github
+!/.mvn
 target
 tmp
 logs