CI: use Ubuntu 24.04; use ubuntu-latest for the ubuntu_build check (#3144)

Now that ubuntu-24 is out of beta at Github

Since for ubuntu_build, we only use one OS version
and the changes between versions are not as drastic as with MacOS,
it seems safe to have it upgrade automatically.

.github/workflows/modified_scripts_build.yml

@@ -157,7 +157,7 @@ jobs:
       fail-fast: false
       matrix:
         python-version: ${{fromJson(needs.discover_modified_scripts.outputs.versions)}}
-        os: ["ubuntu-20.04", "ubuntu-22.04"]
+        os: ["ubuntu-20.04", "ubuntu-22.04", "ubuntu-24.04"]
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4
@@ -215,7 +215,7 @@ jobs:
       fail-fast: false
       matrix:
         python-version: ${{fromJson(needs.discover_modified_scripts.outputs.versions_cpython_only)}}
-        os: ["ubuntu-20.04", "ubuntu-22.04"]
+        os: ["ubuntu-20.04", "ubuntu-22.04", "ubuntu-24.04"]
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4

.github/workflows/pyenv_tests.yml

@@ -10,6 +10,7 @@ jobs:
       fail-fast: false
       matrix:
         os:
+          - ubuntu-24.04
           - ubuntu-22.04
           - ubuntu-20.04
           - macos-14

.github/workflows/ubuntu_build.yml

@@ -15,7 +15,7 @@ jobs:
           - "3.11"
           - "3.12"
           - "3.13"
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
       # Normally, we would use the superbly maintained...