Deprecate JS theme in favor of CSS custom properties (#2158)

.changeset/dry-bugs-sniff.md

@@ -0,0 +1,5 @@
+---
+'@sumup/design-tokens': minor
+---
+
+Exported all CSS custom properties as `@sumup/design-tokens/light.css`.

.changeset/flat-lamps-glow.md

@@ -1,5 +1,4 @@
 ---
-'@sumup/design-tokens': major
 '@sumup/circuit-ui': major
 '@sumup/icons': major
 ---

.changeset/grumpy-donuts-flash.md

@@ -1,5 +1,4 @@
 ---
-'@sumup/design-tokens': major
 '@sumup/circuit-ui': major
 '@sumup/icons': major
 ---

.changeset/late-students-own.md

@@ -0,0 +1,5 @@
+---
+'@sumup/eslint-plugin-circuit-ui': minor
+---
+
+Added `circuit-ui/prefer-custom-properties` rule to replace the Emotion.js theme with CSS custom properties.

.changeset/ninety-months-end.md

@@ -0,0 +1,5 @@
+---
+'@sumup/design-tokens': minor
+---
+
+Deprecated the Emotion.js theme in favor of CSS custom properties. Use the [`circuit-ui/prefer-custom-properties`](https://github.com/sumup-oss/circuit-ui/tree/main/packages/eslint-plugin-circuit-ui/prefer-custom-properties) ESLint rule to automatically migrate your code.

.changeset/red-experts-lie.md

@@ -1,5 +1,4 @@
 ---
-'@sumup/design-tokens': major
 '@sumup/circuit-ui': major
 '@sumup/icons': major
 ---

.eslintrc.js

@@ -13,6 +13,7 @@ module.exports = require('@sumup/foundry/eslint')({
   },
   rules: {
     '@sumup/circuit-ui/no-invalid-custom-properties': 'error',
+    '@sumup/circuit-ui/prefer-custom-properties': 'warn',
     'react/no-unknown-property': ['error', { ignore: ['css'] }],
   },
   parserOptions: {