CI: move `no-response` and `add-version` to `ubuntu-slim`

Supposedly lightweight tasks, we'll see

.github/workflows/add_version.yml

@@ -12,7 +12,7 @@ permissions:
 
 jobs:
   add_cpython:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-slim
     steps:
       - uses: actions/checkout@v6
       - uses: actions/setup-python@v6

.github/workflows/no-response.yml

@@ -15,7 +15,7 @@ jobs:
     permissions:
       issues: write  #  to update issues (lee-dohm/no-response)
 
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-slim
     steps:
       - uses: lee-dohm/no-response@v0.5.0
         with: