Remove version folder when generating meta file template

During release (`./gradlew release`), the build script copy the generated
`.meta` files back to `plugin/Asset` folder to be used as the templates for
future builds, before next release.

This change make sure the version folder is removed from the path in the staging
folder before copying back to the template folder.

Author: chkuang-g

build.gradle

@@ -515,13 +515,17 @@ File versionedAssetFile(File fileObj, Boolean fullVersionPrefix,
 }
 
 /*
- * Remove the version component from a filename.
+ * Remove the version component from a path. (Both its filename and its parent
+ * folder)
  *
  * @param fileObj File to remove version from.
  *
  * @returns File with removed version string.
  */
 File unversionedAssetFile(File fileObj) {
+  // Remove the version postfix. Ex.
+  // "ExternalDependencyManager/Editor/Google.IOSResolver_v1.2.166.dll" ->
+  // "ExternalDependencyManager/Editor/Google.IOSResolver.dll"
   String basename
   String extension
   (basename, extension) = splitFilenameExtension(fileObj)
@@ -537,8 +541,20 @@ File unversionedAssetFile(File fileObj) {
     }
   }
   String filename = basename + extension
-  return fileObj.parent != null ?
-    new File(fileObj.parent, filename) : new File(filename)
+
+  // Remove the version folder as well. Ex.
+  // "ExternalDependencyManager/Editor/1.2.166/Google.IOSResolver.dll" ->
+  // "ExternalDependencyManager/Editor/Google.IOSResolver.dll"
+  def versionFolderRegEx = /^[0-9]+\.[0-9]+\.[0-9]+$/
+  File parent = fileObj.parent != null ? new File(fileObj.parent) : null
+  if (parent != null) {
+      String parentFolder = parent.name
+      def folderMatch = parentFolder =~ versionFolderRegEx
+      if (folderMatch.matches()) {
+          parent = parent.parent != null ? new File(parent.parent) : null
+      }
+  }
+  return parent != null ? new File(parent, filename) : new File(filename)
 }
 
 /*