Updated user guide and cookiecutter template

Author: tomuben

doc/user_guide/features/creating_a_release.rst

@@ -37,6 +37,14 @@ Preparing a release
     * Verify that the version to be released does not already have a git tag or GitHub release
     * Create a new tag & push it to the default branch, which will trigger the GitHub workflow ``cd.yml``
 
+    Additionally, if enabled in your project config, the task will create an additional tag with pattern ``v<MAJOR_VERSION>``.
+    This is especially useful if other projects use Github actions of your project, for example:
+
+    .. code-block:: yaml
+
+        uses: exasol/your_project/.github/actions/your_action@v1
+
+    Your ``PROJECT_CONFIG`` needs to have the flag ``create_major_version_tags=True``.
 
 What to do if the release failed?
 +++++++++++++++++++++++++++++++++

project-template/{{cookiecutter.repo_name}}/noxconfig.py

@@ -19,6 +19,7 @@ class Config:
     path_filters: Iterable[str] = ()
     pyupgrade_args: Iterable[str] = ("--py{{cookiecutter.python_version_min | replace('.', '')}}-plus",)
     plugins: Iterable[object] = ()
+    create_major_version_tags = False
 
 
 PROJECT_CONFIG = Config()