chore: export header

Author: manolakis

.changeset/rude-roses-add.md

@@ -0,0 +1,5 @@
+---
+'chi-wc': patch
+---
+
+export header

package.json

@@ -18,6 +18,7 @@
     "./core": "./packages/core.js",
     "./form-core": "./packages/form-core.js",
     "./foundations": "./packages/foundations.js",
+    "./header": "./packages/header.js",
     "./helpers": "./packages/helpers.js",
     "./icon": "./packages/icon.js",
     "./input": "./packages/input.js",