Clamp Ubuntu version in GitHub action

Author: Cito

.github/workflows/release-docs.yml

@@ -8,7 +8,7 @@ on:
 jobs:
   build:
 
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-24.04
 
     steps:
     - uses: actions/checkout@v5

.github/workflows/test-package.yml

@@ -5,7 +5,7 @@ on: [push]
 jobs:
   build:
 
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     timeout-minutes: 5
     strategy:
       max-parallel: 6