Ignore config directory symlink in development

[frenck]

Proposed change

I've recently adopted a different workflow, allowing me to have multiple git worktrees available using different Python environments (3.9 + 3.10).

I do share the Home Assistant development configuration between those environments using a simple symlink.

mkdir -p ~/code/home-asistant/core
cd ~/code/home-asistant/core

git clone --bare [email protected]:home-assistant/core.git .bare
echo "gitdir: .bare" > .git

# Set up `dev` branch work environment
git worktree add dev
cd dev
pyenv virtualenv 3.9.7 home-assistant-core-3.9.7
pyenv local home-assistant-core-3.9.7
./script/setup

# Take out the config folder, making it centralized
mv ./config ../.config
ln -s ../.config config

Now I can quickly create other worktrees with shared or different environments:

# Create second worktree
cd ~/code/home-asistant/core
git worktree add 3.10 dev
cd 3.10
pyenv virtualenv 3.10.0rc2 home-assistant-core-3.10
pyenv local home-assistant-core-3.10
ln -s ../.config config
./script/setup

Due to this way of working, the development config folder is centralized, however, symlinked.

This PR adjusts the .gitignore to allow both the current and the case in my workflow above.

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes #
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Checklist

• The code change is tested and works locally.
• Local tests pass. Your PR cannot be merged unless tests pass
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• Tests have been added to verify that the new code works.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated for www.home-assistant.io

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  Updated and included derived files by running: python3 -m script.hassfest.
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  Updated by running python3 -m script.gen_requirements_all.
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