gnu: offlineimap: Update to 6.5.7.

* gnu/packages/mail.scm (offlineimap): Update to 6.5.7.

gnu/packages/mail.scm

@@ -288,7 +288,7 @@ (define-public bogofilter
 (define-public offlineimap
   (package
     (name "offlineimap")
-    (version "6.5.5")
+    (version "6.5.7")
     (source (origin
               (method url-fetch)
               (uri (string-append "https://github.com/OfflineIMAP/offlineimap/"
@@ -296,7 +296,7 @@ (define-public offlineimap
               (file-name (string-append name "-" version ".tar.gz"))
               (sha256
                (base32
-                "00k84qagph3xnxss6rkxm61x07ngz8fvffx4z9jyw5baf3cdd32p"))))
+                "18whwc4f8nk8gi3mjw9153c9cvwd3i9i7njmpdbhcplrv33m5pmp"))))
     (build-system python-build-system)
     (native-inputs `(("python" ,python-2)))
     (arguments