remove old version 2.8.0.18 (#6830)

Co-authored-by: Chris Lovett <clovett@microsoft.com>

manifests/Microsoft/XMLNotepad/2.8.0.18.yaml

@@ -1,20 +0,0 @@
-Id: Microsoft.XMLNotepad
-Author: Chris Lovett
-Publisher: Microsoft Corporation
-Name: XML Notepad
-Version: 2.8.0.18
-License: Copyright (C) Microsoft Corporation
-LicenseUrl: https://github.com/microsoft/XmlNotepad/blob/master/LICENSE
-MinOSVersion: 10.0.18362.0
-FileExtensions: xml
-AppMoniker: xmlnotepad
-Tags: xml editor, xml
-Description: XML Notepad is a lightweight and fast tool for editing XML documents.
-Homepage: https://github.com/microsoft/xmlnotepad
-Installers:
-  - Arch: Neutral
-    InstallerType: MSIX
-    Url: http://www.lovettsoftware.com/Downloads/XmlNotepad.Net/XmlNotepadPackage_2.8.0.18_Test/XmlNotepadPackage_2.8.0.18_AnyCPU.msixbundle
-    Sha256: 6e460009e34a7bf7c2e93c78b66fe981b58ad29b0badf8eca49e1f8c57779aa2
-    Language: en
-# Generated by https://github.com/ptorr-msft/WinGetYamlGenerator