Fix locales CDN publish (#5882)

**Problem**  

- `@uppy/locales` on npm used to have `dist` (minified), `lib` (JS),
`src` (to make the sourcemaps work) but dist is redundant tbh and only
for the CDN
- Since the new release tooling only `lib` was published to npm
- CI release could not find any files to upload to CDN (it uses
npm-pack, which checks the "files" in package.json and `dist` was
missing)

**Solution**:

- Correct "files" in package.json's
- Remove `main` from @uppy/locales package.json which pointed to
something random?

We still publish `dist` for `@uppy/locales` needlessly to npm afaik.
Would require a bit more hacking to separate in the current setup

.changeset/fluffy-deer-press.md

@@ -0,0 +1,6 @@
+---
+"@uppy/locales": patch
+"uppy": patch
+---
+
+Add "files" in package.json to only publish what's needed

packages/@uppy/locales/package.json

@@ -4,7 +4,6 @@
   "version": "4.8.3",
   "license": "MIT",
   "type": "module",
-  "main": "locale-pack/index.mjs",
   "scripts": {
     "build": "yarn node script/build-en_US.mjs && tsc --build tsconfig.build.json && yarn format",
     "format": "cd ../../ && yarn check packages/@uppy/locales/src/en_US.ts",
@@ -26,6 +25,8 @@
   },
   "files": [
     "lib",
+    "src",
+    "dist",
     "CHANGELOG.md"
   ],
   "dependencies": {

packages/uppy/package.json

@@ -8,6 +8,12 @@
   "type": "module",
   "unpkg": "dist/uppy.min.js",
   "style": "dist/uppy.min.css",
+  "files": [
+    "src",
+    "lib",
+    "dist",
+    "CHANGELOG.md"
+  ],
   "keywords": [
     "file uploader",
     "drag-drop",