Update version.py (#1557)

Author: seanpmorgan

tensorflow_addons/version.py

@@ -17,7 +17,7 @@
 # We follow Semantic Versioning (https://semver.org/)
 _MAJOR_VERSION = "0"
 _MINOR_VERSION = "8"
-_PATCH_VERSION = "3"
+_PATCH_VERSION = "4"
 
 # When building releases, we can update this value on the release branch to
 # reflect the current release candidate ('rc0', 'rc1') or, finally, the official