Bump version for release (#2507)

Author: tcuongd

R/DESCRIPTION

@@ -1,7 +1,7 @@
 Package: prophet
 Title: Automatic Forecasting Procedure
-Version: 1.1.4
-Date: 2023-05-30
+Version: 1.1.5
+Date: 2023-10-10
 Authors@R: c(
   person("Sean", "Taylor", email = "[email protected]", role = c("cre", "aut")),
   person("Ben", "Letham", email = "[email protected]", role = "aut")