Issue #3341708 by Wim Leers, tedbow, phenaproxima: Update requirements for 3.x

DEVELOPING.md

automatic_updates.info.yml

..._updates_extensions/automatic_updates_extensions.info.yml

.../tests/fixtures/new_module/1.0.0/new_module.info.yml.hide

.../tests/fixtures/new_module/1.1.0/new_module.info.yml.hide

composer.json

package_manager/package_manager.info.yml

...tures/build_test_projects/alpha/1.0.0/alpha.info.yml.hide

...tures/build_test_projects/alpha/1.1.0/alpha.info.yml.hide

...manager/tests/src/Kernel/PathExcluder/GitExcluderTest.php

scripts/install_module.sh

scripts/setup_local_dev.sh

tests/src/Functional/AvailableUpdatesReportTest.php

tests/src/Functional/UpdatePathTest.php