(pip) Install pip on pipeline

.gitlab-ci.yml

@@ -23,6 +23,9 @@ stages:
 build:
     <<: *global_tag_def
     stage: build
+    before_script:
+        - apt install python3-pip
+        - python3 -m pip install scipy==1.11.3 --user
     script:
         - git submodule init
         - git submodule update