gnu: at-spi2-atk: Update to 2.18.1.

* gnu/packages/gtk.scm (at-spi2-atk): Update to 2.18.1.

gnu/packages/gtk.scm

@@ -424,7 +424,7 @@ is part of the GNOME accessibility project.")
 (define-public at-spi2-atk
   (package
    (name "at-spi2-atk")
-   (version "2.16.0")
+   (version "2.18.1")
    (source (origin
             (method url-fetch)
             (uri (string-append "mirror://gnome/sources/" name "/"
@@ -432,7 +432,7 @@ is part of the GNOME accessibility project.")
                                 name "-" version ".tar.xz"))
             (sha256
              (base32
-              "1y9gfz1iz3wpja7s000f0bmyyvc6im5fcdl6bxwbz0v3qdgc9vvq"))))
+              "0bf1g5cj84rmx7p1q547vwbc0hlpcs2wrxnmv96lckfkhs9mzcf4"))))
    (build-system gnu-build-system)
    (arguments
     '(#:phases