gnu: dropbear: Update to 2020.80 [fix for CVE-2018-20685].

* gnu/packages/ssh.scm (dropbear): Update to 2020.80.

gnu/packages/ssh.scm

@@ -465,7 +465,7 @@ (define-public et
 (define-public dropbear
   (package
     (name "dropbear")
-    (version "2019.78")
+    (version "2020.80")
     (source
      (origin
        (method url-fetch)
@@ -473,7 +473,7 @@ (define-public dropbear
              "https://matt.ucc.asn.au/dropbear/releases/"
              "dropbear-" version ".tar.bz2"))
        (sha256
-        (base32 "19242qlr40pbqfqd0gg6h8qpj38q6lgv03ja6sahj9vj2abnanaj"))))
+        (base32 "0jbrbpdzyv11x5rkljdimzq9p6a7da5siw9k405ibnpjj4dr89yr"))))
     (build-system gnu-build-system)
     (arguments `(#:tests? #f))  ; there is no "make check" or anything similar
     ;; TODO: Investigate unbundling libtommath and libtomcrypt or at least