Add .buckconfig.local to .gitignore

Change-Id: I8839516fb825adaf6b8b2e68b1014a20e9ad764f
(cherry picked from commit ea4f9c41bde424a21b1e623b084da1d60833b556)
diff --git a/.gitignore b/.gitignore
index 5160dc9..bbc20cd 100644
--- a/.gitignore
+++ b/.gitignore
@@ -16,6 +16,7 @@
 localDB.*
 .buckd
 buck-out
+.buckconfig.local
 
 core/store/trivial/data/
 core/store/apps