Update linux_push_build.yml

Change linux_push_build to run on supported `ubuntu-latest`

Author: masonova1

.github/workflows/linux_push_build.yml

@@ -3,7 +3,7 @@ run-name: Linux Push Build
 on: [push]
 jobs:
   linux_push_build:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     steps:
       - run: echo "Starting build process"
 
@@ -42,4 +42,4 @@ jobs:
         uses: actions/upload-artifact@v4
         with:
           name: linux-executable
-          path: micropython/ports/unix/build-standard/micropython
+          path: micropython/ports/unix/build-standard/micropython