add missing step how to locally run tests

Author: reubenmiller

README.md

@@ -302,21 +302,27 @@ To run the tests you will need to have python3 >> 3.9 installed on your syste
    C8Y_PASSWORD="mypassword"
    ```
 
-2. Startup the test setup, and bootstrap it
+2. Build the software management plugin
+
+   ```
+   just build
+   ```
+
+3. Startup the test setup, and bootstrap it
 
    ```
    just up
 
    just bootstrap
    ```
 
-3. Setup the python3 virtual environment and install the test dependencies
+4. Setup the python3 virtual environment and install the test dependencies
 
    ```
    just venv
    ```
 
-4. Run the RobotFramework tests
+5. Run the RobotFramework tests
 
    ```
    just test