switch newer ubuntu version

seems like scylla 6.2 cqlsh isn't working
as expect on old versions of glibc

```
2025-01-19 13:51:07.901 DEBUG [cluster:757]:
node1: (EE) /home/runner/.ccm/scylla-repository/release/6.2.2/python3/bin/../libexec/python3.12.bin:
symbol lookup error: /lib/x86_64-linux-gnu/libpthread.so.0: undefined symbol: __libc_pthread_init, version GLIBC_PRIVATE
```

Author: fruch

.github/workflows/integration-tests.yml

@@ -12,7 +12,7 @@ jobs:
   tests:
     name: test ${{ matrix.event_loop_manager }} (${{ matrix.python-version }})
     if: "!contains(github.event.pull_request.labels.*.name, 'disable-integration-tests')"
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-24.04
     strategy:
       fail-fast: false
       matrix: