Issue #2591827 by longwave, neclimdul, elachlan, daffie: Add YAML linting to core coding standards checks

Issue #3128631 by andypost, longwave, hussainweb, ayushmishra206, greg.1.anderson, xjm, catch, Mixologic, jungle, Gábor Hojtsy: Update dependencies composer/composer ^2 and composer/semver to ^3

Issue #3126566 by greg.1.anderson, jungle, tedbow, hussainweb, Kristen Pol, alexpott: Allow Drupal to work with Composer 2

Issue #3117421 by alexpott, swatichouhan012, Mile23, Lendude: Stop trying to run non-existent simpletests on Drupal 9

This reverts commit f9ee64b1.

Issue #3086644 by Mile23, alexpott, Mixologic, greg.1.anderson, jibran: LegacyProject composer templates wrongly reference 8.x + fix test coverage

Issue #3031379 by heddn, Mile23, greg.1.anderson, Charlie ChX Negyesi, alexpott, Mixologic, jibran, catch, Lendude: Add a new test type to do real update testing

Issue #2982680 by greg.1.anderson, mbaynton, Mixologic, jibran, webflo, Mile23, phenaproxima, AaronMcHale, Charlie ChX Negyesi, nicksanta: Add composer-ready project templates to Drupal core

Issue #2983781 by Lendude: Update drupalci.yml concurrency comment to match the new reality of FunctionalJavascript

Issue #2942900 by Mixologic, vaplas, jibran, dawehner, Lendude, martin107, alexpott, tedbow, tacituseu, tstoeckler, heddn: Convert JavascriptTestBase Tests to use DrupalSelenium2Driver

Revert "Issue #2942900 by Mixologic, vaplas, jibran, Lendude, martin107, alexpott, dawehner, tedbow, tacituseu, tstoeckler, heddn: Convert JavascriptTestBase Tests to use DrupalSelenium2Driver"

This reverts commit f55d9746.

Issue #2942900 by Mixologic, vaplas, jibran, Lendude, martin107, alexpott, dawehner, tedbow, tacituseu, tstoeckler, heddn: Convert JavascriptTestBase Tests to use DrupalSelenium2Driver