remove accidental asciicast2gif dependency

Author: transitive-bullshit

package.json

@@ -22,7 +22,6 @@
     "publish"
   ],
   "dependencies": {
-    "asciicast2gif": "^0.1.4",
     "consolidate": "^0.15.0",
     "cp-file": "^5.0.0",
     "execa": "^0.9.0",