gnu: python2-pillow: Fix build.

* gnu/packages/python-xyz.scm (python2-pillow): Downgrade to version 6.2.2.

gnu/packages/python-xyz.scm

@@ -5703,7 +5703,18 @@ a general image processing tool.")
               "The PIL Software License"))))
 
 (define-public python2-pillow
-  (package-with-python2 python-pillow))
+  (package-with-python2
+   (package
+     (inherit python-pillow)
+     ;; Version 6 is the last series with Python 2 support.
+     (version "6.2.2")
+     (source
+     (origin
+       (method url-fetch)
+       (uri (pypi-uri "Pillow" version))
+       (sha256
+        (base32
+         "0l5rv8jkdrb5q846v60v03mcq64yrhklidjkgwv6s1pda71g17yv")))))))
 
 (define-public python-pillow-2.9
   (package