changelog: v1.6.3

- Add v1.6.3 to changelog
- Remove capa rules from v1.6.2 (there were no changes). I'll remove the
tag in capa-rules once this is merged.
- Remove master (unreleased) section. This only makes sense in master
and we are only using this branch for backporting bug fixes.

CHANGELOG.md

@@ -1,21 +1,16 @@
 # Change Log
 
-## master (unreleased)
+## v1.6.3 (2021-04-29)
 
-### New Features
-
-### New Rules
-
-### Bug Fixes
+This release adds IDA 7.6 support to capa.
 
 ### Changes
 
-### Development
+- IDA 7.6 support @williballenthin @Ana06
 
 ### Raw diffs
-<!-- The diff uses v1.6.1 because master doesn't include v1.6.2 -->
-- [capa v1.6.1...master](https://github.com/fireeye/capa/compare/v1.6.1...master)
-- [capa-rules v1.6.1...master](https://github.com/fireeye/capa-rules/compare/v1.6.1...master)
+
+  - [capa v1.6.2...v1.6.3](https://github.com/fireeye/capa/compare/v1.6.2...v1.6.3)
 
 
 ## v1.6.2 (2021-04-13)
@@ -29,7 +24,6 @@ This release backports a fix to capa 1.6: The Windows binary was built with Pyth
 ### Raw diffs
 
   - [capa v1.6.1...v1.6.2](https://github.com/fireeye/capa/compare/v1.6.1...v1.6.2)
-  - [capa-rules v1.6.1...v1.6.2](https://github.com/fireeye/capa-rules/compare/v1.6.1...v1.6.2)
 
 
 ## v1.6.1 (2021-04-07)