electron_33-bin: mark as insecure because it's EOL

https://github.com/electron/electron/blob/3041fd66cddac32cd1dc6a129e1edd46fe2c77ce/docs/tutorial/electron-timelines.md

pkgs/development/tools/electron/binary/generic.nix

···
     ];
     sourceProvenance = with sourceTypes; [ binaryNativeCode ];
     # https://www.electronjs.org/docs/latest/tutorial/electron-timelines
-    knownVulnerabilities = optional (versionOlder version "33.0.0") "Electron version ${version} is EOL";
+    knownVulnerabilities = optional (versionOlder version "34.0.0") "Electron version ${version} is EOL";
   };
 
   fetcher =