Update Drupal Core to v8.9.20 (8.x)

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
drupal/core-composer-scaffold (source)	require	patch	8.9.19 -> 8.9.20
drupal/core-dev-pinned	require-dev	patch	8.9.19 -> 8.9.20
drupal/core-project-message (source)	require	patch	8.9.19 -> 8.9.20
drupal/core-recommended	require	patch	8.9.19 -> 8.9.20

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Release Notes

drupal/core-composer-scaffold

### [`v8.9.20`](https://togithub.com/drupal/core-composer-scaffold/compare/8.9.19...8.9.20) [Compare Source](https://togithub.com/drupal/core-composer-scaffold/compare/8.9.19...8.9.20)

drupal/core-dev-pinned

### [`v8.9.20`](https://togithub.com/drupal/core-dev-pinned/compare/8.9.19...8.9.20) [Compare Source](https://togithub.com/drupal/core-dev-pinned/compare/8.9.19...8.9.20)

drupal/core-project-message

### [`v8.9.20`](https://togithub.com/drupal/core-project-message/compare/8.9.19...8.9.20) [Compare Source](https://togithub.com/drupal/core-project-message/compare/8.9.19...8.9.20)

drupal/core-recommended

### [`v8.9.20`](https://togithub.com/drupal/core-recommended/compare/8.9.19...8.9.20) [Compare Source](https://togithub.com/drupal/core-recommended/compare/8.9.19...8.9.20)

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