Gulp modifying package version in prepublish script - Doesn't work

gulpfile.js

var gulp = require('gulp');
var jsonTransform = require("gulp-json-transform");

gulp.task('removeGH', function() {
  gulp
    .src('package.json')
    .pipe(jsonTransform(function(data) {
      if (data.version.indexOf("-GH") === data.version.length - 3)
        data.version = data.version.substring(0, data.version.length - 3);
      return data;
    }, 4))
    .pipe(gulp.dest('.'));
});

gulp.task('prepublish', ['removeGH']);

gulp.task('default', []);

package.json

{
    "name": "some_test_npm_package",
    "version": "1.0.0-GH",
    "description": "Just trying to find out some stuff about npm",
    "main": "index.js",
    "scripts": {
        "prepublish": "gulp prepublish",
        "test": "echo \"Error: no test specified\" && exit 1"
    },
    "author": "roblabla",
    "license": "MIT",
    "devDependencies": {
        "gulp": "^3.8.11",
        "gulp-json-transform": "^0.2.0"
    }
}