tacent: fix tag

pkgs/by-name/ta/tacent/package.nix

···
   src = fetchFromGitHub {
     owner = "bluescan";
     repo = "tacent";
-    tag = finalAttrs.version;
+    tag = "v${finalAttrs.version}";
     hash = "sha256-z8VuJS8OaVw5CeO/udvBEmcURKIy1oWVYUv6Ai8lTI8=";
   };