feature #1385 Add support for Svelte 5 (Kocal)

This PR was squashed before being merged into the main branch.

Discussion
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Add support for Svelte 5

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes <!-- please update CHANGELOG.md file -->
| Deprecations? | no <!-- please update CHANGELOG.md file -->
| Issues        | Fix #1384 <!-- prefix each issue number with "Fix #", no need to create an issue if none exists, explain below instead -->
| License       | MIT

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Commits
-------

f4fcf4d Fix functional test on PostCSS/Autoprefixer
fa91367 Add support for Svelte 5

Author: Kocal

CHANGELOG.md

@@ -1,5 +1,9 @@
 # CHANGELOG
 
+## 5.3.0
+
+* Add support for Svelte 5
+
 ## 5.2.0 
 
 * Add support for Webpack CLI ^6.0.0

fixtures/js/hello_world.svelte

@@ -1,5 +1,5 @@
 <script>
-	let name = 'world';
+	let name = $state('world');
 </script>
 
 <h1>Hello {name}!</h1>

package.json

@@ -93,7 +93,7 @@
     "strip-ansi": "^6.0.0",
     "stylus": "^0.63.0",
     "stylus-loader": "^7.0.0 || ^8.1.0",
-    "svelte": "^3.50.0 || ^4.2.2",
+    "svelte": "^3.50.0 || ^4.2.2 || ^5.0.0",
     "svelte-loader": "^3.1.0",
     "ts-loader": "^9.0.0",
     "typescript": "^5.0.0",

test/functional.js

@@ -1055,6 +1055,9 @@ module.exports = {
                 `
             );
 
+            // Force very old Safari to ensure that autoprefixer will prefix `backdrop-filter`
+            fs.writeFileSync(path.join(appDir, '.browserslistrc'), 'Safari 9');
+
             const config = testSetup.createWebpackConfig(appDir, 'www/build', 'dev');
             config.enableSingleRuntimeChunk();
             config.setPublicPath('/build');