Update github runner image to ubuntu 24.04 (#31)

20.04 is no longer supported, see actions/runner-images#11101

Author: jannic

.github/workflows/build.yml

@@ -3,7 +3,7 @@ name: Build and Test check
 jobs:
   builds:
     name: Build checks
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-24.04
     strategy:
       matrix:
         mode: ["", "--release"]