Fix for issue #10 lastModifiedBy undefined - lastModifiedBy should be…

… config.LastModifiedBy

extension.js:
* Added another field into the config, called lastModifiedBy (because existing fields are all read only, and although it is unlkely, we were previously catering for the eventuality that last modified is undefined in the settings, and referring to that by a local variable 'lastModifiedBy', which was later removed - the afore mentioned error occured because older code that referred to this variable had been committed wrongly. So this new field does the same job.

extension.js

@@ -2,7 +2,7 @@
  * @Author: mikey.zhaopeng
  * @Date:   2016-07-29 15:57:29
  * @Last Modified by: Noscere
- * @Last Modified time: 2022-11-15 06:15:56.517
+ * @Last Modified time: 2022-11-15 07:22:32.354
  */
 
 var vscode = require('vscode');
@@ -13,6 +13,7 @@ Date.prototype.format = fileheader.dateFormat;
 
 function getConfig() {
     var config = vscode.workspace.getConfiguration('fileheader');
+    config.lastModifiedBy = config.LastModifiedBy;
     if(config.Author) {
         // Sanity check - shouldn't be null, but you never know
         if(config.LastModifiedBy) {
@@ -95,7 +96,7 @@ function activate(context) {
             var data = {
                 author: config.Author,
                 email: config.Email,
-                lastModifiedBy: lastModifiedBy, // use local variable assigned above
+                lastModifiedBy: config.lastModifiedBy, // use local variable assigned in getConfig()
                 createTime: time,
                 updateTime: time,
                 description: description