chore: Add .stylelintrc file to add rules

frappe/.stylelintrc

@@ -0,0 +1,8 @@
+ {
+	extends: ["stylelint-config-recommended"],
+	plugins: ["stylelint-scss"],
+	rules: {
+		"at-rule-no-unknown": null,
+		"scss/at-rule-no-unknown": true
+	}
+};