update the CI to hopefully improve readability for new users

.gitlab-ci.yml

 default:
   image: python:3.12-slim
 
-.install_dependencies:
-  before_script:
-    - pip install --upgrade pip
-    - pip install setuptools wheel build twine
+workflow:
+  rules:
+    - if: '$CI_PIPELINE_SOURCE == "web"'
+    - if: '$CI_COMMIT_BRANCH == "main"'
+
+variables:
+  PACKAGE_NAME: "pak"
+  REPO_URL: "${CI_API_V4_URL}/projects/${CI_PROJECT_ID}/packages/pypi"
+  PIP_CACHE_DIR: "${CI_PROJECT_DIR}/.cache/pip"
+  PIP_INDEX_URL: "https://__token__:${CI_JOB_TOKEN}@gitlab.com/api/v4/projects/${CI_PROJECT_ID}/packages/pypi/simple"
+  PIP_EXTRA_INDEX_URL: "https://pypi.org/simple"
 
 stages:
   - build
   - test
   - publish
 
-variables:
-  PACKAGE_NAME: "pak"
-
 build_package:
   stage: build
-  extends: .install_dependencies
   script:
+    - pip install --upgrade pip
+    - pip install setuptools wheel build
     - python -m build
   artifacts:
     paths:
       - dist/*
+  cache:
+    paths:
+      - ${PIP_CACHE_DIR}
 
 test_package:
   stage: test
   script:
-    - pip install .  # Install the package
+    - pip install .  
     - pip install pytest
-    - pytest  # Run tests
+    - pytest 
 
 publish_pip:
   stage: publish
-  extends: .install_dependencies
-  variables:
-    PIP_CACHE_DIR: "$CI_PROJECT_DIR/.cache/pip"
-    PIP_INDEX_URL: "https://__token__:${CI_JOB_TOKEN}@gitlab.com/api/v4/projects/$CI_PROJECT_ID/packages/pypi/simple"
-    PIP_EXTRA_INDEX_URL: "https://pypi.org/simple"
   script:
-    - TWINE_PASSWORD=${CI_JOB_TOKEN} TWINE_USERNAME=gitlab-ci-token python3 -m twine upload --repository-url ${CI_API_V4_URL}/projects/${CI_PROJECT_ID}/packages/pypi dist/*
+    - pip install twine
+    - twine upload -u gitlab-ci-token -p ${CI_JOB_TOKEN} --repository-url ${REPO_URL} dist/*
 
 build_and_push_docker_image:
   stage: publish
-  image: docker:26.0.1
+  image: docker:latest
   services:
-    - docker:26.0.1-dind
+    - docker:dind
   variables:
-    DOCKER_IMAGE_NAME: $CI_REGISTRY_IMAGE/$PACKAGE_NAME:$CI_COMMIT_REF_SLUG
+    DOCKER_IMAGE_NAME: ${CI_REGISTRY_IMAGE}/${PACKAGE_NAME}
     DOCKER_TLS_CERTDIR: "/certs"
   before_script:
-    - docker login -u "$CI_REGISTRY_USER" -p "$CI_REGISTRY_PASSWORD" $CI_REGISTRY
+    - echo "${CI_REGISTRY_PASSWORD}" | docker login -u "${CI_REGISTRY_USER}" --password-stdin ${CI_REGISTRY}
   script:
-    - docker build --pull -t "$DOCKER_IMAGE_NAME" .
-    - docker push "$DOCKER_IMAGE_NAME"
-    - |
-      if [[ "$CI_COMMIT_BRANCH" == "$CI_DEFAULT_BRANCH" ]]; then
-        docker tag "$DOCKER_IMAGE_NAME" "$CI_REGISTRY_IMAGE:latest"
-        docker push "$CI_REGISTRY_IMAGE:latest"
-      fi
-
-  only:
-    - main  # Only run on the main branch
+    - echo "Building docker image and tagging as latest"
+    - docker pull ${DOCKER_IMAGE_NAME}:latest || true
+    - docker build --build-arg BUILDKIT_INLINE_CACHE=1 --cache-from ${DOCKER_IMAGE_NAME}:latest -t ${DOCKER_IMAGE_NAME}:latest .
+    - docker push ${DOCKER_IMAGE_NAME}:latest