Update gulpfile.js

Fixed gulpfile syntax for newer systems

samples/react-kanban-board/gulpfile.js

@@ -10,43 +10,45 @@ build.addSuppression(`Warning - [sass] The local CSS class 'ms-Grid' is not came
 // Stefan rocks!
 let syncVersionsSubtask = build.subTask('version-sync', function (gulp, buildOptions, done) {
     this.log('Synching versions');
-    
+
     // import gulp utilits to write error messages
     const gutil = require('gulp-util');
-    
+
     // import file system utilities form nodeJS
     const fs = require('fs');
-    
+
     // read package.json
     var pkgConfig = require('./package.json');
-    
+
     // read configuration of web part solution file
     var pkgSolution = require('./config/package-solution.json');
-    
+
     // log old version
     this.log('package-solution.json version:\t' + pkgSolution.solution.version);
-    
+
     // Generate new MS compliant version number
     var newVersionNumber = pkgConfig.version.split('-')[0] + '.0';
-    
+
     if (pkgSolution.solution.version !== newVersionNumber) {
-    // assign newly generated version number to web part version
+        // assign newly generated version number to web part version
-    pkgSolution.solution.version = newVersionNumber;
+        pkgSolution.solution.version = newVersionNumber;
-    
+
-    // log new version
+        // log new version
-    this.log('New package-solution.json version:\t' + pkgSolution.solution.version);
+        this.log('New package-solution.json version:\t' + pkgSolution.solution.version);
-    
+
-    // write changed package-solution file
+        fs.writeFile('./config/package-solution.json', JSON.stringify(pkgSolution, null, 4), function (err, result) {
-    fs.writeFile('./config/package-solution.json', JSON.stringify(pkgSolution, null, 4));
+            if (err) this.log('error', err);
+        });
+
     }
     else {
-    this.log('package-solution.json version is up-to-date');
+        this.log('package-solution.json version is up-to-date');
     }
-    
+
     done();
-    }); 
+});
-    let syncVersionTask = build.task('version-sync', syncVersionsSubtask);
+let syncVersionTask = build.task('version-sync', syncVersionsSubtask);
-    build.rig.addPreBuildTask(syncVersionTask);
+build.rig.addPreBuildTask(syncVersionTask);