Fix test failures on main branch

Committing this from needs review to try to get main to a green pipeline. Nothing controversial in here hopefully, retrospective reviews would be appreciated though.

I looked at it. It's disappointing that we can't use dev-main in those Composer requirements because that means it's just one more thing we have to keep up to date with versions. I'm not deeply familiar with how the Composer scaffolding works, but I can see how dev-main just wouldn't work there. It makes sense to me.

As a tradeoff we only have to update some numbers once every two years, so effort in fixing this is probably better spent elsewhere.

Agreed. I'd rather see us move forward with switching to the main branch sooner rather than hold it up for something that's so easily handled.

Not sure if we should re-open this and resolve here, or handle it in separate issues, but I still can't get a core MR to run tests against main.

https://git.drupalcode.org/project/drupal/-/merge_requests/14347/pipelines

First, the issue fork branch was off 11.x while the MR defaulted to targeting main. That led to all the jobs failing in composer validate with:

In VersionParser.php line 191:
                                     
  Invalid version string "main-dev"

https://git.drupalcode.org/issue/drupal-3567589/-/pipelines/712207

Then, I rebased to main, tried again. Now, thanks to .gitlab-ci.yml, we're trying to install drupal/config_inspector but there's no D12 release:

Your requirements could not be resolved to an installable set of packages.
  Problem 1
    - Root composer.json requires drupal/config_inspector * -> satisfiable by drupal/config_inspector[dev-1.x, dev-2.0.x, dev-2.1.x, 1.0.0-alpha1, ..., 1.x-dev, 2.0.1, ..., 2.1.x-dev].
    - drupal/config_inspector[1.0.0-alpha1, ..., 1.0.0-beta2] require drupal/core ^8 -> found drupal/core[8.0.0-beta6, ..., 8.9.x-dev] but it conflicts with your root composer.json require (12.x-dev).
    - drupal/config_inspector[dev-1.x, dev-2.0.x, 1.0.0, ..., 1.x-dev, 2.0.1, ..., 2.0.x-dev] require drupal/core ^8 || ^9 -> found drupal/core[8.0.0-beta6, ..., 8.9.x-dev, 9.0.0-alpha1, ..., 9.5.x-dev] but it conflicts with your root composer.json require (12.x-dev).
    - drupal/config_inspector[2.1.0, ..., 2.1.4] require drupal/core ^9.2 || ^10 -> found drupal/core[9.2.0-alpha1, ..., 9.5.x-dev, 10.0.0-alpha1, ..., 10.6.x-dev] but it conflicts with your root composer.json require (12.x-dev).
    - drupal/config_inspector[dev-2.1.x, 2.1.5, ..., 2.1.x-dev] require drupal/core ^9.2 || ^10 || ^11 -> found drupal/core[9.2.0-alpha1, ..., 9.5.x-dev, 10.0.0-alpha1, ..., 10.6.x-dev, 11.0.0-alpha1, ..., 11.x-dev] but it conflicts with your root composer.json require (12.x-dev).
Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.
You can also try re-running composer require with an explicit version constraint, e.g. "composer require drush/drush:*" to figure out if any version is installable, or "composer require drush/drush:^2.1" if you know which you need.
Installation failed, reverting ./composer.json and ./composer.lock to their original content.

https://git.drupalcode.org/issue/drupal-3567589/-/pipelines/712242

Curious why composer complains/fail for `main` branch when it should be reported as dev-main

UnexpectedValueException: Invalid version string "main" in
Composer\Semver\VersionParser->normalize() (line 186 of
/var/www/d9/vendor/composer/semver/src/VersionParser.php).