Support Ubuntu 24.04

The "ubuntu-latest" image in GitHub Actions has gradually started using mapping to Ubuntu 24.04:
actions/runner-images#10636

Currently this gives an error from "setup-ghdl-ci":

  Error: Ubuntu version 24.04 is not supported!

.github/workflows/test.yml

@@ -15,7 +15,7 @@ jobs:
       fail-fast: false
       matrix:
         backend: [ '', mcode, llvm, gcc ]
-        version: [ 20.04, 22.04, latest ]
+        version: [ 20.04, 22.04, 24.04, latest ]
     runs-on: ubuntu-${{ matrix.version }}
     name: '🐧 Ubuntu ${{ matrix.version }} · ${{ matrix.backend }}'
     steps:

README.md

@@ -8,7 +8,7 @@
 
 **setup-ghdl-ci** is a JavaScript GitHub Action (GHA) to setup GHDL using [nightly](https://github.com/ghdl/ghdl/releases/tag/nightly) release assets. Latest packages are retrieved and installed along with required dependencies, to enable testing of VHDL designs in Continuous Integration (CI) workflows.
 
-Currently, GitHub Actions workflow tasks running on Ubuntu or Windows are supported only. Precisely [environments](https://github.com/actions/virtual-environments#available-environments) `ubuntu-20.04`, `ubuntu-22.04`|`ubuntu-latest`, `windows-2019` or `windows-2022`|`windows-latest` can be used.
+Currently, GitHub Actions workflow tasks running on Ubuntu or Windows are supported only. Precisely [environments](https://github.com/actions/virtual-environments#available-environments) `ubuntu-20.04`, `ubuntu-22.04`, `ubuntu-24.04`|`ubuntu-latest`, `windows-2019` or `windows-2022`|`windows-latest` can be used.
 
 Contributions for supporting addional [platforms](https://help.github.com/en/actions/reference/virtual-environments-for-github-hosted-runners#supported-runners-and-hardware-resources) or CI services are welcome! For instance, GHDL is already tested on GitHub Actions `macos-latest`, but packaging is not done yet.
 

main.js

@@ -24,7 +24,7 @@ async function run() {
       if ( await exec.exec('sed', ['-n', 's/^VERSION_ID="\\(.*\\)".*/\\1/p', '/etc/os-release'], options) ) {
         throw new Error(`Could not read os version ID from '/etc/os-release!`);
       };
-      if ( osVersion !== '20.04' && osVersion !== '22.04' ) {
+      if ( osVersion !== '20.04' && osVersion !== '22.04' && osVersion !== '24.04' ) {
         throw new Error(`Ubuntu version ${ osVersion.replace(/^\s+|\s+$/g, '') } is not supported!`);
       }
     }