Fix discord server invitation

Closes #4393

Author: Pierre-Sassoulas

doc/development_guide/contribute.rst

@@ -33,7 +33,7 @@ astroid:
 Discord server
 --------------
 
-https://discord.gg/kFebW799
+https://discord.gg/Egy6P8AMB5
 
 Mailing lists
 -------------

setup.cfg

@@ -33,7 +33,7 @@ keywords = static code analysis linter python lint
 project_urls =
     What's New = https://pylint.pycqa.org/en/latest/whatsnew/
     Bug tracker = https://github.com/PyCQA/pylint/issues
-    Discord server = https://discord.gg/kFebW799
+    Discord server = https://discord.gg/Egy6P8AMB5
     User manual = http://pylint.pycqa.org/en/latest/
     Contributing = http://pylint.pycqa.org/en/latest/development_guide/contribute.html
     Technical references = http://pylint.pycqa.org/en/latest/technical_reference/index.html