[Dev Deps] pin jackspeak since 2.1.2+ depends on npm aliases, which kill the install process in npm < 6

See isaacs/jackspeak#4

Author: ljharb

package.json

@@ -18,6 +18,7 @@
 		"eslint": "=8.8.0",
 		"evalmd": "^0.0.19",
 		"in-publish": "^2.0.1",
+		"jackspeak": "=2.1.1",
 		"npmignore": "^0.3.0",
 		"nyc": "^10.3.2",
 		"safe-publish-latest": "^2.0.0",