.github: workflows: Add test trigger for pytest harness

Pytest twister harness tests have been added to the
twister_tests.yml workflow some time ago.

However, the $ZEPHYR_BASE/scripts/pylib/pytest-twister-harness/**
has not been monitored by the automatic GitHub Action triggers
of that workflow.

This change adds monitoring for the relevant files.

Signed-off-by: Lukasz Mrugala <[email protected]>

Author: LukaszMrugala

.github/workflows/twister_tests.yml

@@ -9,7 +9,7 @@ on:
     - main
     - v*-branch
     paths:
-    - 'scripts/pylib/twister/**'
+    - 'scripts/pylib/**'
     - 'scripts/twister'
     - 'scripts/tests/twister/**'
     - '.github/workflows/twister_tests.yml'
@@ -18,7 +18,7 @@ on:
     - main
     - v*-branch
     paths:
-    - 'scripts/pylib/twister/**'
+    - 'scripts/pylib/**'
     - 'scripts/twister'
     - 'scripts/tests/twister/**'
     - '.github/workflows/twister_tests.yml'