Bump to 4.0-alpha-1.
diff --git a/gradle.properties b/gradle.properties
index d338b8f..3edfd0d 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -1,3 +1,3 @@
-thisVersion=3.9-SNAPSHOT
+thisVersion=4.0-alpha-1
 
 apiCompatVersion=3.8