Do not support Ubuntu 20.04 anymore (EVerest#174)

Signed-off-by: Andreas Heinrich <[email protected]>

docs/general/02_detail_pre_setup.rst

@@ -58,7 +58,11 @@ Tested Environments
 Ubuntu
 ------
 
-Tested with Ubuntu 20.04 and 22.04.
+.. warning::
+
+  Ubuntu 20.04 is not supported anymore. Please use Ubuntu 22.04 or newer.
+
+Tested with Ubuntu 22.04.
 
 Use `apt` to get your needed libraries installed:
 
@@ -69,18 +73,6 @@ Use `apt` to get your needed libraries installed:
 
 Please make sure to have `nodejs` installed with minimum version 10.20 for `node_api` version 6+. For updating to a supported version, please follow the install procedure here: `<https://github.com/nodesource/distributions/blob/master/README.md#installation-instructions>`_.
 
-.. note::
-
-  Using Ubuntu 20.04, it will be required to use clang-format version greater
-  than 11. To date, `apt` does only install an older version, so we install
-  version 12 manually:
-
-  `sudo apt install clang-format-12`
-
-  Then make Ubuntu use version 12:
-
-  `sudo update-alternatives --install /usr/bin/clang-format clang-format /usr/bin/clang-format-12 100`
-
 OpenSUSE
 --------
 Use `zypper` to get your needed libraries installed: