chore(deps): update dependency composer/installers to v2

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
composer/installers (source)	require	major	^1.12 -> ^2.0

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Release Notes

composer/installers

### [`v2.0.1`](https://togithub.com/composer/installers/blob/HEAD/CHANGELOG.md#v201---2021-09-13) [Compare Source](https://togithub.com/composer/installers/compare/v2.0.0...v2.0.1) ##### Fixed - Fixed installer for Pantheon Quicksilver modules/scripts [#​494](https://togithub.com/composer/installers/pull/494). ### [`v2.0.0`](https://togithub.com/composer/installers/blob/HEAD/CHANGELOG.md#v200---2021-08-04) [Compare Source](https://togithub.com/composer/installers/compare/v1.12.0...v2.0.0) ##### Added - Added installer for Pantheon Quicksilver modules/scripts [#​492](https://togithub.com/composer/installers/pull/492). - Added installer for Akaunting modules [#​489](https://togithub.com/composer/installers/pull/489). ##### Removed - Removed support for TYPO3 Flow

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