Merge pull request #40 from cksource/t/37

Remove GeSHi lub from `codesnippetgeshi` plugin

plugins/codesnippetgeshi/README.md

@@ -1,4 +1,8 @@
 Code Snippet GeSHi Plugin
 ==================================================
 
+The [GeSHi library](https://github.com/GeSHi/geshi-1.0) is no longer actively maintained. Due to the lack of ongoing support and updates, potential security vulnerabilities have been identified with its continued use. To mitigate these risks and enhance the overall security of the CKEditor 4, we have decided to completely remove the GeSHi library as a dependency. This change aims to maintain a secure environment and reduce the risk of any security incidents related to outdated or unsupported software.
+
+To integrators who still want to use the GeSHi syntax highlighter, we recommend manually adding the GeSHi library. Please be aware of and understand the potential security vulnerabilities associated with its use.
+
 For installation and configuration instructions go to the [Code Snippet GeSHi documentation](https://ckeditor.com/docs/ckeditor4/latest/features/codesnippetgeshi.html) in the [CKEditor Developer's Guide](https://ckeditor.com/docs/ckeditor4/latest/guide.html).