Prepare 6.0.0 release

Author: ezzatron

CHANGELOG.md

@@ -1,5 +1,12 @@
 # Phony for PHPUnit changelog
 
+## 6.0.0 (2020-01-06)
+
+This release uses *Phony* `4.x`. There no BC breaking API changes aside from
+stricter type declarations.
+
+- **[BC BREAK]** PHP 7.1 is no longer supported.
+
 ## 5.0.0 (2019-02-05)
 
 - **[BC BREAK]** Dropped support for PHPUnit `7.x` ([#3], [#4]).

composer.json

@@ -42,7 +42,7 @@
     },
     "extra": {
         "branch-alias": {
-            "dev-master": "6.0.x-dev"
+            "dev-master": "6.1.x-dev"
         }
     }
 }