Update change log for 6.1.3

Author: christophwille

.github/workflows/dotnet.yml

@@ -16,7 +16,7 @@ jobs:
     env:
         Solution: '**/ICSharpCode.AvalonEdit.sln'
         BuildPlatform: 'Any CPU'
-        BuildVersion: '6.1.3'
+        BuildVersion: '6.1.4'
     steps:
     - uses: actions/checkout@v2
     - name: Update project version

ChangeLog.md

@@ -1,7 +1,12 @@
 Note: this changelog only lists major changes and fixes for major bugs. For a complete list of changes, see the git log.
 
-tbd: AvalonEdit 6.1.3
+tbd: AvalonEdit X
+* 
+
+2021/12/28: AvalonEdit 6.1.3
 * TFM changes: net6.0-windows (LTS) added
+* Expose MarkerPen and MarkerCornerRadius on SearchPanel
+* Fix TSQL highlighting where a backslash exists before a single quote literal ('') in a string
 
 2021/06/01: AvalonEdit 6.1.2
 * TFM changes: netcoreapp3.0 removed in favor of netcoreapp3.1 (LTS), net5.0-windows added