tests: move to ubuntu 22.04

Drop ubuntu 20.04 as it will be unsupported on march 2025
actions/runner-images#11101

Author: iMichka

.github/workflows/tests.yml

@@ -14,62 +14,65 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - os: ubuntu-20.04
+          # UBUNTU 24.04 - CASTXML EPIC 0
+          - os: ubuntu-22.04
             compiler: gcc
-            version: "9"
+            version: "11"
             python-version: "3.9"
             castxml: "castxml"
             castxml-epic: 0
             cppstd: "-std=c++98"
 
-          - os: ubuntu-20.04
+          - os: ubuntu-22.04
             compiler: gcc
-            version: "9"
+            version: "11"
             python-version: "3.10"
             castxml: "castxml"
             castxml-epic: 0
             cppstd: "-std=c++98"
 
-          - os: ubuntu-20.04
+          - os: ubuntu-22.04
             compiler: gcc
-            version: "9"
+            version: "11"
             python-version: "3.11"
             castxml: "castxml"
             castxml-epic: 0
             cppstd: "-std=c++98"
 
-          - os: ubuntu-20.04
+          - os: ubuntu-22.04
             compiler: gcc
-            version: "9"
+            version: "11"
             python-version: "3.12"
             castxml: "castxml"
             castxml-epic: 0
             cppstd: "-std=c++98"
 
-          - os: ubuntu-20.04
+          - os: ubuntu-22.04
             compiler: gcc
-            version: "9"
+            version: "11"
             python-version: "3.13"
             castxml: "castxml"
             castxml-epic: 0
             cppstd: "-std=c++98"
 
-          - os: ubuntu-20.04
+          # UBUNTU 24.04 - CASTXML EPIC 1
+          - os: ubuntu-22.04
             compiler: gcc
-            version: "9"
+            version: "11"
             python-version: "3.13"
             castxml: "castxml"
             castxml-epic: 1
             cppstd: "-std=c++98"
 
-          - os: ubuntu-20.04
+          - os: ubuntu-22.04
             compiler: gcc
-            version: "9"
+            version: "11"
             python-version: "3.13"
             castxml: "castxml"
             castxml-epic: 1
             cppstd: "-std=c++11"
 
+          # MACOS
           - os: macos-13
             compiler: xcode
             version: "default"