jasper: mark as vulnerable

Many memory issues remain unfixed or partially fixed:
CVE-2018-18873 CVE-2018-19539 CVE-2018-19540 CVE-2018-19541
CVE-2018-9252 CVE-2018-19542 CVE-2018-19543 CVE-2018-20570
CVE-2018-20584 CVE-2018-20622 CVE-2018-9252

Debian/Ubuntu, OpenSuSE and Gentoo removed it entirely. See:
jasper-software/jasper#208

pkgs/development/libraries/jasper/default.nix

@@ -42,5 +42,10 @@ stdenv.mkDerivation rec {
     platforms = platforms.unix;
     license = licenses.jasper;
     maintainers = with maintainers; [ pSub ];
+    knownVulnerabilities = [
+      "Numerous CVE unsolved upstream"
+      "See: https://github.com/NixOS/nixpkgs/pull/57681#issuecomment-475857499"
+      "See: https://github.com/mdadams/jasper/issues/208"
+    ];
   };
 }