Add Directory Structure for androidx.dataStore

Bug: 149110240
Test: gw bOS
Change-Id: I6b9fde98082939406b03c59a9a053b33f168fa60
diff --git a/datastore/datastore-preferences/api/restricted_1.0.0-alpha01.txt b/datastore/datastore-preferences/api/restricted_1.0.0-alpha01.txt
new file mode 100644
index 0000000..da4f6cc
--- /dev/null
+++ b/datastore/datastore-preferences/api/restricted_1.0.0-alpha01.txt
@@ -0,0 +1 @@
+// Signature format: 3.0