package.json: bump version to 1.2.9

Signed-off-by: Huang Rui <vowstar@gmail.com>

Author: vowstar

package-lock.json

@@ -52,5 +52,5 @@
     "test": "nyc --reporter=lcov mocha --reporter spec --timeout 200000",
     "coverage": "cat ./coverage/lcov.info | coveralls"
   },
-  "version": "1.2.8"
+  "version": "1.2.9"
 }