reset ballista branch to apache/master (#2641)

Author: korowa

dev/build-arrow-ballista.sh

@@ -24,7 +24,7 @@ rm -rf arrow-ballista 2>/dev/null
 
 # clone the repo
 # TODO make repo/branch configurable
-git clone --branch join_filter https://github.com/korowa/arrow-ballista
+git clone https://github.com/apache/arrow-ballista
 
 # update dependencies to local crates
 python ./dev/make-ballista-deps-local.py