Update dependency ubuntu to v24 (#559)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/autoupdate.yml

@@ -6,7 +6,7 @@ on:
 jobs:
   autoupdate:
     name: autoupdate
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-24.04
     steps:
       - uses: docker://chinthakagodawita/autoupdate-action:v1
         env:

.github/workflows/combine-prs.yml

@@ -9,7 +9,7 @@ on:
 jobs:
   combine-prs:
     name: "Combine Renovate Pull Requests"
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-24.04
     steps:
       - uses: hmcts/am-github-actions/combine-prs@master
         name: "Combine Renovate Pull Requests"