ci: Minor change.

.gitlab-ci.yml

@@ -331,7 +331,7 @@ build-windows:
     - mkdir windows
     - cd windows
     # Setup env
-    - pip3 install -U pip
+    - python -m pip install -U pip
     - python -m pip install -r ..\requirements.txt
     - python -m pip install -U -r ..\requirements.txt
     # Run Pyinstaller