CI: The Happy New Year license PR

[gmuloc]

Change Summary

Update years in License headers and files used to generate some headers (plugins doc template & `development/license-short.txt)

[github-actions]

Review docs on Read the Docs

To test this pull request:

# Create virtual environment for this testing below the current directory
python -m venv test-avd-pr-4847
# Activate the virtual environment
source test-avd-pr-4847/bin/activate
# Install all requirements including PyAVD
pip install "pyavd[ansible] @ git+https://github.com/gmuloc/avd.git@happy-new-year-2025#subdirectory=python-avd" --force
# Point Ansible collections path to the Python virtual environment
export ANSIBLE_COLLECTIONS_PATH=$VIRTUAL_ENV/ansible_collections
# Install Ansible collection
ansible-galaxy collection install git+https://github.com/gmuloc/avd.git#/ansible_collections/arista/avd/,happy-new-year-2025 --force
# Optional: Install AVD examples
cd test-avd-pr-4847
ansible-playbook arista.avd.install_examples