update workflow: get list of modified tests

.github/workflows/plugins.yml

@@ -13,6 +13,7 @@ on:
       - '.github/packaging/centreon-plugin.yaml.template'
       - 'src/**'
       - 'packaging/**'
+      - 'tests/**'
   push:
     branches:
       - develop
@@ -32,6 +33,8 @@ jobs:
     runs-on: ubuntu-22.04
     outputs:
       plugins: ${{ steps.get_plugins.outputs.plugins }}
+      unit_tests: ${{ steps.filter.outputs.unit_tests }}
+      robot_tests: ${{ steps.filter.outputs.robot_tests }}
     steps:
       - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
         with:
@@ -54,6 +57,12 @@ jobs:
               - added|modified: packaging/**
             plugins:
               - added|modified: src/**
+            robot_tests:
+              - added|modified: tests/**/*.robot
+              - added|modified: tests/**/*.json
+              - added|modified: tests/**/*.snmpwalk
+            unit_tests:
+              - added|modified: tests/**/*.t
 
       - name: transform to directories
         run: |