fix bin path

Author: azu

package.json

@@ -14,7 +14,7 @@
   "description": "日本語で書かれた技術書のコーパス",
   "main": "lib/index.js",
   "bin": {
-    "technological-book-corpus-ja.js": "./bin/technological-book-corpus-ja.js"
+    "technological-book-corpus-ja": "./bin/technological-book-corpus-ja.js"
   },
   "scripts": {
     "build": "node build.js",