usbd: Add missing manifest file.

Author: projectgus

micropython/usbd/manifest.py

@@ -0,0 +1,15 @@
+metadata(version="0.1.0")
+
+# TODO: split this up into sub-packages, and some code in example subdirectory
+package(
+    "usbd",
+    files=(
+        "__init__.py",
+        "device.py",
+        "hid.py",
+        "hid_keypad.py",
+        "midi.py",
+        "utils.py",
+    ),
+    base_path="..",
+)