gnu: cups: Update to 2.3.3 [fixes CVE-2020-3898 & CVE-2019-8842].

* gnu/packages/cups.scm (cups-minimal, cups)[replacement]: New fields.
(cups-minimal-2.3.3, cups-2.3.3): New public variables.

gnu/packages/cups.scm

@@ -187,6 +187,7 @@ (define-public cups-filters
 ;; satisfy this dependency.
 (define-public cups-minimal
   (package
+    (replacement cups-minimal-2.3.3)
     (name "cups-minimal")
     (version "2.3.1")
     (source
@@ -249,8 +250,22 @@ (define-public cups-minimal
     ;; CUPS is Apache 2.0 with exceptions, see the NOTICE file.
     (license license:asl2.0)))
 
+(define-public cups-minimal-2.3.3
+  (package
+    (inherit cups-minimal)
+    (version "2.3.3")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (string-append "https://github.com/apple/cups/releases/download/v"
+                           version "/cups-" version "-source.tar.gz"))
+       (sha256
+        (base32
+         "1vpk0b2vq830f8fvf9z8qjsm5k141i7pi8djbinpnr78pi4dj7r6"))))))
+
 (define-public cups
   (package (inherit cups-minimal)
+    (replacement cups-2.3.3)
     (name "cups")
     (arguments
      `(;; Three tests fail:
@@ -392,6 +407,12 @@ (define-public cups
        ("cups-filters" ,cups-filters)
        ("zlib"  ,zlib)))))
 
+(define-public cups-2.3.3
+  (package
+    (inherit cups)
+    (version "2.3.3")
+    (source (package-source cups-minimal-2.3.3))))
+
 (define-public cups-pk-helper
   (package
     (name "cups-pk-helper")