Update README.md outdated links

Signed-off-by: Hofi <hofione@gmail.com>

README.md

@@ -2,29 +2,22 @@
 
 # Welcome to the syslog-ng OSE documentation center source repository
 
-[gh:gh-doc-pages]: https://syslog-ng.github.io/doc/
-[gh:gh-syslog-ng-doc-issue-tracker]: https://github.com/syslog-ng/doc/issues
-[ref:doc-guide]: doc/_doc-guide
-[ref:doc-guide-contrib]: doc/_doc-guide/README.md#how-to-contribute-to-the-documentation
-[ref:admin-guide]: doc/_admin-guide
-[ref:dev-guide]: doc/_dev-guide
-
 Here you can browse, search and contribute to most of the syslog-ng OSE documentation.
 
-## [Documentation guide][ref:doc-guide]
+## [Documentation guide](https://syslog-ng.github.io/doc-guide/README)
 
-If you would like to help us to make our documentation better, this is [how to contribute][ref:doc-guide-contrib].
+If you would like to help us to make our documentation better, this is [how to contribute](https://syslog-ng.github.io/doc-guide/README#how-to-contribute-to-the-documentation).
 
-## [Administration guide][ref:admin-guide]
+## [Administration guide](https://syslog-ng.github.io/admin-guide/README)
 
 This repository part contains the source code of `The syslog-ng OSE Administration Guide`.
 
-## [Developer guide][ref:dev-guide]
+## [Developer guide](https://syslog-ng.github.io/dev-guide/README)
 
-Do you like adding your idea, bug-fix to the fabolous syslog-ng? Help others to do the same, share your knwowledge in the [developer guide][ref:dev-guide].
+Do you like adding your idea, bug-fix to the fabolous syslog-ng? Help others to do the same, share your knwowledge in the [developer guide](https://syslog-ng.github.io/dev-guide/README).
 
-## [Generated document][gh:gh-doc-pages]
+## [Generated document](https://syslog-ng.github.io/)
 
 [![Deploy Jekyll site to Pages](https://github.com/syslog-ng/syslog-ng.github.io/actions/workflows/jekyll-gh-pages.yml/badge.svg)](https://github.com/syslog-ng/syslog-ng.github.io/actions/workflows/jekyll-gh-pages.yml)
 
-We use github to track all of the [documentation issues][gh:gh-syslog-ng-doc-issue-tracker]
+We use github to track all of the [documentation issues](https://github.com/syslog-ng/syslog-ng.github.io/issues)