Merge branch 'package-ci-doc-update' into 'master'

Update Composer and PyPI docs with additional info

See merge request gitlab-org/gitlab!40617

doc/user/packages/composer_repository/index.md

@@ -80,6 +80,10 @@ Now that the basics of our project is completed, we can publish the package.
 To publish the package, you need:
 
 - A personal access token. You can generate a [personal access token](../../../user/profile/personal_access_tokens.md) with the scope set to `api` for repository authentication.
+   NOTE: **Note:**
+
+  [Deploy tokens](./../../project/deploy_tokens/index.md) are not yet supported for use with Composer.
+
 - Your project ID which can be found on the home page of your project.
 
 To publish the package hosted on GitLab, make a `POST` request to the GitLab package API.

doc/user/packages/pypi_repository/index.md

@@ -248,6 +248,13 @@ Uploading mypypipackage-0.0.1.tar.gz
 This indicates that the package was uploaded successfully. You can then navigate
 to your project's **Packages & Registries** page and see the uploaded packages.
 
+If you would rather not use a `.pypirc` file to define your repository source,
+you can upload to the repository with the authentication inline:
+
+```shell
+TWINE_PASSWORD=<personal_access_token or deploy_token> TWINE_USERNAME=<username or deploy_token_username> python3 -m twine upload --repository-url https://gitlab.com/api/v4/projects/<project_id>/packages/pypi dist/*
+```
+
 If you did not follow the guide above, then you need to ensure your package
 has been properly built and you [created a PyPi package with `setuptools`](https://packaging.python.org/tutorials/packaging-projects/).
 
@@ -292,3 +299,32 @@ Collecting mypypipackage
 Installing collected packages: mypypipackage
 Successfully installed mypypipackage-0.0.1
 ```
+
+## Using GitLab CI with PyPI packages
+
+NOTE: **Note:**
+`CI_JOB_TOKEN`s are not yet supported for use with PyPI.
+
+To work with PyPI commands within [GitLab CI/CD](./../../../ci/README.md), you can use
+[environment variables](./../../../ci/variables/README.md#custom-environment-variables)
+to access your authentication tokens in your commands.
+
+Set up environment variables for `TWINE_PASSWORD` and `TWINE_USERNAME` using either:
+
+- A [personal access token](../../../user/profile/personal_access_tokens.md) and your GitLab username.
+- A [deploy token](./../../project/deploy_tokens/index.md) and its associated deploy token username.
+
+You can now access your `TWINE_USERNAME` and `TWINE_PASSWORD` using any `twine` command in your
+`.gitlab-ci.yml` file.
+
+For example:
+
+```yaml
+image: python:latest
+
+run:
+  script:
+    - pip install twine
+    - python setup.py sdist bdist_wheel
+    - TWINE_PASSWORD=${TWINE_PASSWORD} TWINE_USERNAME=${TWINE_USERNAME} python -m twine upload --repository-url https://gitlab.com/api/v4/projects/${CI_PROJECT_ID}/packages/pypi dist/*
+```