Bump xosapi and xosgenx dependency to 4.0.0

Change-Id: I0165963cfd04ce70f6bb76aaad41d83a7681d25a
diff --git a/VERSION b/VERSION
index 456ea72..227cea2 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-1.3.3-dev
+2.0.0
diff --git a/requirements.txt b/requirements.txt
index c39dc6b..d200ebb 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,4 @@
 tosca-parser~=1.4.0
-xosgenx~=3.2.7
-xosapi~=3.0.5
+xosgenx~=4.0.0
+xosapi~=4.0.0
 klein~=17.10.0