[3.13] Pin the doctest workflow to Ubuntu 22.04 (GH-125236) (#125240)

Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 4462bfa..89bf7b1 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -42,7 +42,7 @@
 
   check_abi:
     name: 'Check if the ABI has changed'
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     needs: check_source
     if: needs.check_source.outputs.run_tests == 'true'
     steps:
diff --git a/.github/workflows/reusable-docs.yml b/.github/workflows/reusable-docs.yml
index 4b021b3..7755cb4 100644
--- a/.github/workflows/reusable-docs.yml
+++ b/.github/workflows/reusable-docs.yml
@@ -95,7 +95,7 @@
   # Run "doctest" on HEAD as new syntax doesn't exist in the latest stable release
   doctest:
     name: 'Doctest'
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     timeout-minutes: 60
     steps:
     - uses: actions/checkout@v4