Update .gitlab-ci.yml file

.gitlab-ci.yml

+image: python:3.10
+
+stages:
+  - build
+  - deploy
+
+variables:
+  GIT_SUBMODULE_STRATEGY: recursive
+  PAGES_DIR: public
+
+before_script:
+  - python -m pip install --upgrade pip
+  - pip install furo
+  - pip install sphinx
+  - pip install sphinx-rtd-theme
+
+build:
+  stage: build
+  script:
+    - mkdir -p $PAGES_DIR
+    - sphinx-build -b html docs $PAGES_DIR
+  artifacts:
+    paths:
+      - $PAGES_DIR
+
+pages:
+  stage: deploy
+  script:
+    - echo "Deploying GitLab Pages"
+  artifacts:
+    paths:
+      - $PAGES_DIR
+    expire_in: 30 days
+  only:
+    - main