Update templated requirements to current releases

[BrianHenryIE]

scaffold-package-command generates a composer.json using relatively old package versions.

scaffold-package-command/templates/composer.mustache

Lines 8 to 13 in c309cf5

	"require": {
	"wp-cli/wp-cli": "{{require_wp_cli}}"
	},
	"require-dev": {
	"wp-cli/wp-cli-tests": "{{require_wp_cli_tests}}"
	},

This PR updates the defaults provided in the PhpDoc to the current releases:

• wp-cli/wp-cli current is v2.10.0
• wp-cli/wp-cli-tests current release is v4.3.1

[ernilambar]

Feature tests should also be updated.
May be we can wait for "2.11" which is going to released in a couple of days.

[BrianHenryIE]

No urgency, but I'm not sure what exactly you're referring to with "Feature tests".

Really, the wp-cli/wp-cli update from ^2.5 to ^2.10.0 won't make a practical difference, wp-cli/wp-cli-tests from ^3.0.11 to ^4.3.1 (^4) is where I noticed an issue.

Edit: tests are failing anyway, I'll have to spend more time on this!

[ernilambar]

https://github.com/wp-cli/scaffold-package-command/blob/main/features/scaffold-package-readme.feature#L43 should also be updated with new value.

[ernilambar]

WP-CLI 2.11 has been released.