title: Grunt bump package.json version
body: <p>I would like to add 'release' task:</p>
  
  <pre class="lang-js prettyprint-override"><code>grunt.initConfig({
    ...
    shell: {
      release: {
        command: function(version) {
          return 'git checkout -b release-' + version + ' devel';
        }
      }
    }
    ...
    grunt.loadNpmTasks('grunt-bumpup');
    grunt.loadNpmTasks('grunt-shell');
    ...
    grunt.registerTask('release', function() {
      grunt.task.run('bumpup');
      var version = grunt.config.get('pkg').version;
      grunt.task.run('shell:release:' + version);
    });
  </code></pre>
  
  <p>But I have the following:</p>
  
  <pre><code>Running "release" task
  
  Running "bumpup" task
  Bumped to: 1.2.5
  
  Running "shell:release:1.2.4" (shell) task
  Switched to a new branch 'release-1.2.4'
  M   Gruntfile.js
  M   package.json
  M   src/manifest.json
  
  Done, without errors.
  </code></pre>
  
  <p>So the version was bumped up, but branch was created for previous version.</p>
  
  <p>I think it is because package.json cached. Can I reread it?</p>
  
  <pre><code> var version = grunt.file.readJSON('package.json').version; // old version too
  </code></pre>
  
  <p><strong>EDIT:</strong></p>
  
  <p>Adding 'updateProps' to bumpup config will change pkg version property, but:</p>
  
  <pre><code>grunt.registerTask('release', function() {
    grunt.task.run('bumpup');
  
    var version = grunt.config.get('pkg').version;
    grunt.log.writeln(version); // old version, because tasks run async?
  
    grunt.task.run('shell:release:' + version);
  });
  </code></pre>
  
  <p>Works good:</p>
  
  <pre><code>grunt.initConfig({
    pkg: grunt.file.readJSON('package.json'),
    ...
    bumpup: {
      options: {
        updateProps: {
          pkg: 'package.json'
        }
      },
      files: ['package.json', 'src/manifest.json']
    },
    shell: {
      release: {
        command: function() {
          return 'git checkout -b release-' + grunt.config.get('pkg').version + ' devel';
        }
      }
    },
    ...
    grunt.loadNpmTasks('grunt-bumpup');
    grunt.loadNpmTasks('grunt-shell');
    ...
    grunt.registerTask('release', ['lint', 'bumpup', 'shell:release']);
  </code></pre>