Set project version to 1.6.0 (#222)

diff --git a/Project.toml b/Project.toml
index 072ab4d..22b8723 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "Arrow"
 uuid = "69666777-d1a9-59fb-9406-91d4454c9d45"
 authors = ["quinnj <quinn.jacobd@gmail.com>"]
-version = "1.5.0"
+version = "1.6.0"
 
 [deps]
 ArrowTypes = "31f734f8-188a-4ce0-8406-c8a06bd891cd"