refactor: add changelog

CHANGELOG

+
+1.0
+======
+
+Release notes for 1.0.0
+
+Features
+--------
+
+- Shipping API
+- Shipping Method Management
+    - Allow certain Shipping methods only for certain groups of people
+    - Define different shipping costs for time periods
+    - Set different shipping costs for specific products
+- Different rules can be assigned to each shipping method
+- Each rule has a variety of adjustment options
+    - Priority
+    - Discount
+    - Unit rule
+    - Usage from / to
+    - Shopping amouunt of / to
+    - Purchase value of / to
+    - User specification
+    - Product specification