chore(release): Prepare version 3.0.4

Author: pgrigoruta

CHANGELOG.md

@@ -3,12 +3,18 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
-## [Unreleased](https://github.com/contentful/contentful-core.php/compare/3.0.3...HEAD)
+## [Unreleased](https://github.com/contentful/contentful-core.php/compare/3.0.4...HEAD)
 
 <!-- PENDING-CHANGES -->
 > No meaningful changes since last release.
 <!-- /PENDING-CHANGES -->
 
+## [3.0.4](https://github.com/contentful/contentful-core.php/tree/3.0.4) (2020-09-15)
+
+### Added
+
+Fixed a few static code analysis issues
+
 ## [3.0.3](https://github.com/contentful/contentful-core.php/tree/3.0.3) (2020-09-15)
 
 ### Added