Bedrock: Create project with --prefer-source --remove-vcs

[tangrufus]

Add --prefer-source --remove-vcs flags so that users will get git export-ignore files.

$ composer create-project --no-install --prefer-source --remove-vcs roots/bedrock with-prefer-source

$ composer create-project --no-install roots/bedrock without-prefer-source

$ diff -qr with-prefer-source without-prefer-source
Only in with-prefer-source: .devcontainer
Only in with-prefer-source: .editorconfig
Only in with-prefer-source: .gitattributes
Only in with-prefer-source: .github

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The --prefer-source flag significantly slows down the create-project command because it installs dependencies from source as well. Alternatively, we could:

composer create-project --no-install --prefer-source --remove-vcs roots/bedrock
cd bedrock
composer install

[tangrufus]

Side note: $ trellis new suffer from the same issue.

• https://github.com/roots/trellis-cli/blob/831cfcf819e7076d337914246856f1a6ccd76fd5/cmd/new.go#L131
• https://github.com/roots/trellis-cli/blob/831cfcf819e7076d337914246856f1a6ccd76fd5/cmd/new.go#L120