Move "composer/installers" package to require-dev.

[mreishus]

Changes proposed in this Pull Request:

I found that wpcomsh was shipping with a large number of installer files in vendor and in the classmap:

These don't look relevant to anything we need to do. Tracing it down, this dependency was added here when adding linting commands to the repo: #90

It might have also been added here instead: a9a44f4

As far as I can tell, composer/installers lets you install plugins to places other than vendor/, but I don't see it being used here. @anomiex also ran into some issues from it being included here: Automattic/jetpack#37737 (comment)

I think that means this is only needed for development (if at all), and we don't need to be including this when shipping the plugin. I searched for instances of "installer" and don't see it being used anywhere.

How to test the changes in this Pull Request:

• Have you followed the Writing high-quality testing instructions guide?

Other information:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your changes, as applicable?

FOR PR REVIEWER ONLY:

• I have reviewed that everything is sanitized/escaped appropriately for any SQL or XSS injection possibilities. I made sure Linting is not ignored or disabled.

[github-actions]

Size Change: 0 B

Total Size: 201 kB

ℹ️ View Unchanged

Filename	Size
./build/53.js	1.08 kB
./build/index.css	731 B
./build/index.js	126 kB
./build/marketing.js	58.3 kB
./build/payment-gateway-suggestions.css	1.24 kB
./build/payment-gateway-suggestions.js	6.57 kB
./build/plugins.js	3.93 kB
./build/style-index.css	2.15 kB
./build/style-marketing.css	800 B

_{compressed-size-action}

[ivan-ottinger]

Hey, @mreishus. 👋🏼 I am probably not the most suitable person to judge the change proposed in this PR so will let it for others.

Thanks for the review request anyways!

[obenland]

@Automattic/somewherewarm Could you help with a review for this PR?

[chihsuan]

LGTM. 👍 I did a quick test on a E-commerce plan site and all seems to be working fine. Thanks for the PR. @mreishus

[PanosSynetos]

Hey @obenland - SomewhereWarm hasn't worked with Calypso Bridge for over six months. Someone that is using Calypso Bridge on a daily basis, should be better suited to test this on out.

[ilyasfoo]

Thanks for reviewing, @chihsuan!

@mreishus Apologies to have missed this earlier. I've also tested this change in a business and a ecommerce plan site. I'm unsure how to fully test the change, but what I did was:

1. In a fresh clone, run npm install, composer install, and npm run build and observed no related error message
2. Upload the entire directory to wp-content/mu-plugins/wpcomsh/vendor/automattic/wc-calypso-bridge of the site
3. Tested wp-admin and frontend and observed no error
4. Looked at wp php-errors and observed no error
5. Looked at wp-content/debug.log and observed no error

I've also updated the changelog in 23f91b7.

LGTM, feel free to merge. Let me know if you need help with deploying

[mreishus]

Thanks for the review! Created deploy PR #1526