chore: update Python setup step to specify version 3.14

Signed-off-by: Ntege Daniel <danientege785@gmail.com>

Author: danielmarv

.github/workflows/publish.yml

@@ -12,7 +12,7 @@ permissions:
 jobs:
   build:
     name: Build distributions
-    runs-on: hl-sdk-py-lin-md
+    runs-on: ubuntu-latest
 
     steps:
       - name: Harden the runner (Audit all outbound calls)
@@ -53,7 +53,7 @@ jobs:
     concurrency:
       group: ${{ github.workflow }}-${{ github.ref }}
       cancel-in-progress: false
-    runs-on: hl-sdk-py-lin-md
+    runs-on: ubuntu-latest
     environment:
       name: pypi
       url: https://pypi.org/p/hiero-sdk-python