Prep to release packages

[jakemac53]

Releases support for analyzer 7.x and dart_style 3.x.

closes #3780 and #3779

This also brings all packages back into the pub workspace by having a unified min SDK of 3.6.0, now that we have a stable release.

[github-actions]

PR Health

Changelog Entry ✔️

Package	Changed Files

Changes to files need to be accounted for in their respective changelogs.

[jakemac53]

Ignoring warnings about test fixtures package configs which are git ignored, they should not actually be ignored afaict, and don't need to ship with the package in any case.

[github-actions]

Package publishing

Package	Version	Status	Publish tag (post-merge)
package:build	2.4.2	ready to publish	build-v2.4.2
package:build_config	1.1.2	ready to publish	build_config-v1.1.2
package:build_daemon	4.0.3	ready to publish	build_daemon-v4.0.3
package:build_modules	5.0.10	ready to publish	build_modules-v5.0.10
package:build_resolvers	2.4.3	ready to publish	build_resolvers-v2.4.3
package:build_runner	2.4.14	ready to publish	build_runner-v2.4.14
package:build_runner_core	8.0.0	ready to publish	build_runner_core-v8.0.0
package:build_test	2.2.3	ready to publish	build_test-v2.2.3
package:build_web_compilers	4.1.0	ready to publish	build_web_compilers-v4.1.0
package:scratch_space	1.0.3-wip	WIP (no publish necessary)

Documentation at https://github.com/dart-lang/ecosystem/wiki/Publishing-automation.