Fix one char typo in DESCRIPTION (closes #423)

Author: eddelbuettel

DESCRIPTION

@@ -2,7 +2,7 @@ Package: RcppArmadillo
 Type: Package
 Title: 'Rcpp' Integration for the 'Armadillo' Templated Linear Algebra Library
 Version: 0.12.6.4.0
-Date: 2024-09-06
+Date: 2023-09-06
 Author: Dirk Eddelbuettel, Romain Francois, Doug Bates, Binxiang Ni, and Conrad Sanderson
 Maintainer: Dirk Eddelbuettel <[email protected]>
 Description: 'Armadillo' is a templated C++ linear algebra library (by Conrad