add changelog for the feature branch

CHANGELOG-FEATURE.md

@@ -0,0 +1,35 @@
+# Feature changelog: serverside apply
+
+This is a list of things this feature branch changes from head. The point is not
+history (you can get that from git) but keeping an up-to-date snapshot of the
+changes. So, when you make a change it is legit to either add something here,
+modify something, or even reshuffle the organization system.
+
+Current organization is copied from the project map document.
+
+1. API Types and Toolchain (OpenAPI)
+    1.1. New Go IDL Tags
+    1.2. New OpenAPI extensions tags
+    1.3. OpenAPI Compilation toolchain
+    1.4. Fix-up existing APIs
+    1.5. CRD (`validation` field) compatible spec
+2. Merging
+    2.1. Ownership semantic
+    2.2. Merge logic
+3. Machinery/Wiring
+    3.1. New PATCH handler Content-Type
+    3.2. Metadata API Change
+        - Added a map[workflow-id]last-applied-state to metadata.
+    3.3. OpenAPI data model wiring to strategy/registry
+    3.4. Updated PUT Handler
+    3.5. Admission chain
+    3.6. Conversion/Defaulting
+    3.7. Validation
+4. User Experience
+    4.1. Kubectl
+    4.2. Version skew and upgrade path
+    4.3. Dry-run
+5. Feature Health
+    5.1. Testing
+    5.2. Monitoring
+    5.3. Documentation