Update pub-pypi.yml

Author: k01ek

.github/workflows/pub-pypi.yml

@@ -7,7 +7,7 @@ on:
 jobs:
   build-n-publish:
     name: Build and publish Python 🐍 distributions 📦 to PyPI and TestPyPI
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@main
     - name: Set up Python 3.7