github: Update 'ubuntu-22.04' to 'ubuntu-latest' (#1022)

There was some inconsistency in the GitHub Workflow files on using
'ubuntu-latest' (which gets the latest Ubuntu version) or
'ubuntu-22.04'. To keep things consistent 'ubuntu-latest' is now used in
all cases. This also saves us updating workloads upon release of a new
Ubuntu version.

.github/workflows/ci-tests.yaml

@@ -14,7 +14,7 @@ concurrency:
 jobs:
     pre-commit:
     # runs on github hosted runner
-        runs-on: ubuntu-22.04
+        runs-on: ubuntu-latest
         if: github.event.pull_request.draft == false
         steps:
             - uses: actions/checkout@v4
@@ -24,7 +24,7 @@ jobs:
   # ensures we have a change-id in every commit, needed for gerrit
     check-for-change-id:
         # runs on github hosted runner
-        runs-on: ubuntu-22.04
+        runs-on: ubuntu-latest
         if: github.event.pull_request.draft == false
         steps:
             - uses: actions/checkout@v4
@@ -189,7 +189,7 @@ jobs:
     # merged. The 'testlib-quick-execution' is a matrix job which runs all the
     # the testlib quick tests. This job is therefore a stub which will pass if
     # all the testlib-quick-execution jobs pass.
-        runs-on: ubuntu-22.04
+        runs-on: ubuntu-latest
         needs: testlib-quick-execution
         steps:
             - run: echo "This job's status is ${{ job.status }}."