Use correct python version in lightning component template (#13790)

use correct python version in lightning component template

Co-authored-by: manskx <[email protected]>
(cherry picked from commit 4588a79)

Author: manskx

src/lightning_app/cli/component-template/.github/workflows/ci-testing.yml

@@ -16,7 +16,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-20.04, macOS-10.15, windows-2019]
-        python-version: [3.7]
+        python-version: [3.8]
 
     # Timeout: https://stackoverflow.com/a/59076067/4521646
     timeout-minutes: 35