Upgrade github workflow to use latest ubuntu

The ubuntu-18.04 environment is deprecated, consider switching to ubuntu-20.04(ubuntu-latest),
or ubuntu-22.04 instead.
For more details see actions/runner-images#6002

Author: michael.yak

.github/workflows/python_package_build.yml

@@ -8,7 +8,7 @@ on:
 
 jobs:
   run_image:
-    runs-on: [ubuntu-18.04]
+    runs-on: [ubuntu-latest]
     container:
       image: matanrubin/python-poetry:3.9
 

.github/workflows/python_package_publish.yml

@@ -8,7 +8,7 @@ on:
 
 jobs:
   run_image:
-    runs-on: [ubuntu-18.04]
+    runs-on: [ubuntu-latest
     container:
       image: matanrubin/python-poetry:3.9