add pynx-igor to plugin tests

Author: lukaspie

.github/workflows/plugin_test.yaml

@@ -28,7 +28,9 @@ jobs:
             tests_to_run: tests/.
           - plugin: pynxtools-em
             branch: main
-            tests_to_run: tests/.
+          - plugin: pynxtools-igor
+            branch: main
+            tests_to_run: tests/.    
           - plugin: pynxtools-mpes
             branch: main
             tests_to_run: tests/.