Add aapt2 to gitignore

Change-Id: Ia0737310f7776011027654a08fc28c1703ced5b3
diff --git a/.gitignore b/.gitignore
index d6d767e..e684d2e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -29,6 +29,8 @@
 tests/2016-12-19/art.tar.gz
 tests/2017-10-04/art
 tests/2017-10-04/art.tar.gz
+third_party/aapt2/
+third_party/aap2.tar.gz
 third_party/api_database/api_database
 third_party/api_database/api_database.tar.gz
 third_party/api-outlining/simple-app-dump