refactor(ButtonBase): To use CSS modules behind the feature flag

.changeset/olive-donkeys-exercise.md

@@ -0,0 +1,5 @@
+---
+"@primer/react": major
+---
+
+Refactor ButtonBase component to use CSS modules behine flag

.vscode/settings.json

@@ -10,6 +10,13 @@
   "[typescriptreact]": {
     "editor.defaultFormatter": "esbenp.prettier-vscode"
   },
+  "[postcss]": {
+    "editor.defaultFormatter": "esbenp.prettier-vscode",
+    "editor.formatOnSave": true,
+    "editor.codeActionsOnSave": {
+      "source.fixAll.stylelint": "explicit"
+    }
+  },
   "json.schemas": [
     {
       "fileMatch": ["*.docs.json"],