Add magento-composer-installer to allowed plugins

[elidrissidev]

Description (*)

A recent change in Composer regarding the allow-plugins config been causing the Sonar workflow to fail with error message:

magento-hackathon/magento-composer-installer contains a Composer plugin which is blocked by your allow-plugins config. You may add it to the list if you consider it safe.

This PR will add magento-hackathon/magento-composer-installer to allowed plugins in composer.json.

Manual testing scenarios (*)

1. All tests should now pass, hopefully.

Contribution checklist (*)

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All automated tests passed successfully (all builds are green)
• Add yourself to contributors list

[elidrissidev]

All green! ✅

[github-actions]

Unit Test Results

1 files  ±0  1 suites  ±0   0s ⏱️ ±0s
0 tests ±0  0 ✔️ ±0  0 💤 ±0  0 ❌ ±0 
7 runs  ±0  5 ✔️ ±0  2 💤 ±0  0 ❌ ±0 

Results for commit 61e3c4d. ± Comparison against base commit 5bf1ab5.

[fballiano]

I still see a lot of composer errors in the workflow, @elidrissidev do you know what's happening?

[elidrissidev]

@fballiano 20 branch does not contain this fix yet.

[fballiano]

ah oki it's just that, ok

[fballiano]

thanks!