Update Cake to the latest 2.x version (#2500)

.config/dotnet-tools.json

@@ -3,7 +3,7 @@
   "isRoot": true,
   "tools": {
     "cake.tool": {
-      "version": "2.1.0",
+      "version": "2.3.0",
       "commands": [
         "dotnet-cake"
       ]

cake/UpdateDocs.cake

@@ -43,8 +43,7 @@ void CopyChangelogs (DirectoryPath diffRoot, string id, string version)
 Task ("docs-download-output")
     .Does (async () =>
 {
-    EnsureDirectoryExists ("./output");
-    CleanDirectories ("./output");
+    CleanDir ("./output");
 
     await DownloadPackageAsync ("_nugets", OUTPUT_NUGETS_PATH);
     await DownloadPackageAsync ("_nugetspreview", OUTPUT_NUGETS_PATH);
@@ -55,7 +54,7 @@ Task ("docs-download-output")
             ? $"{version}-{PREVIEW_NUGET_SUFFIX}"
             : version;
         var name = $"{id}.{localNugetVersion}.nupkg";
-        CleanDirectories ($"./output/{id}");
+        CleanDir ($"./output/{id}");
         Unzip ($"{OUTPUT_NUGETS_PATH}/{name}", $"./output/{id}/nuget");
     }
 });