feature #1224 Add "type: module" for all packages and changing main -> module (weaverryan)

This PR was merged into the 2.x branch.

Discussion
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Add "type: module" for all packages and changing main -> module

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| Tickets       | None
| License       | MIT

Follow up on https://github.com/symfony/ux/pull/1202/files#r1367791334

We already use ESM inside of our packages. This makes that official with `type: module`. Some notes / questions:

A) I believe, since we already ONLY made "modules" available, that this will have no effect on end users, but I'm not 100% sure about that. If someone is using `require` instead of `import`, it would affect them... but in that case, I believe `require` would not have worked before anyway. But if anyone knows better than I do, I'd appreciate your notes.

B) Because we are a `type: module`, my impression is that `main` will not be used. And we can instead rely on `module`.

tl;dr I believe these changes won't have user-facing effects, but I'm not 100% sure about that... though I'm pretty sure that if they DO have user-facing effects, it would be limited to people who are currently using `require` with these packages.

Cheers!

Commits
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592be5e683 Specifically adding type: module for all packages and changing main -> module

Author: weaverryan

assets/package.json

@@ -3,7 +3,8 @@
     "description": "Swup integration for Symfony",
     "license": "MIT",
     "version": "1.1.0",
-    "main": "dist/controller.js",
+    "module": "dist/controller.js",
+    "type": "module",
     "types": "dist/controller.d.ts",
     "symfony": {
         "controllers": {