downgrade ubuntu

Author: vincentsarago

.github/workflows/ci.yml

@@ -20,7 +20,7 @@ env:
 
 jobs:
   tests:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     strategy:
       matrix:
         python-version: ['3.8', '3.9', '3.10', '3.11']
@@ -65,7 +65,7 @@ jobs:
 
   benchmark:
     needs: [tests]
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v3
       - name: Set up Python