update matrix

Author: martinssipenko

README.md

@@ -11,7 +11,7 @@ interfaces.
 
 ## Author and copyright
 
-Martin Helmich <kontakt@martin-helmich.de>  
+Martin Helmich <kontakt@martin-helmich.de>
 This library is [MIT-licensed](LICENSE.txt).
 
 ## Installation
@@ -24,11 +24,12 @@ There are several release branches of this library, each of these being compatib
 with different releases of PHPUnit and PHP. The following table should give an
 easy overview:
 
-| PSR-7 assertion version | PHPUnit 4 | PHPUnit 5 | PHPUnit 6 | PHPUnit 7 |
+| PSR-7 assertion version | PHPUnit 4 | PHPUnit 5 | PHPUnit 6 | PHPUnit 7 | PHPUnit 8 |
 | ----------------------- | --------- | --------- | --------- | --------- |
-| v1 (branch `v1`), **unsupported** | :white_check_mark: | :white_check_mark: | :no_entry_sign: | :no_entry_sign: |
-| v2 (branch `v2`) | :no_entry_sign: | :no_entry_sign: | :white_check_mark: | :no_entry_sign: |
-| v3 (branch `master`) | :no_entry_sign: | :no_entry_sign: | :no_entry_sign: | :white_check_mark: |
+| v1 (branch `v1`), **unsupported** | :white_check_mark: | :white_check_mark: | :no_entry_sign: | :no_entry_sign: | :no_entry_sign: |
+| v2 (branch `v2`) | :no_entry_sign: | :no_entry_sign: | :white_check_mark: | :no_entry_sign: | :no_entry_sign: |
+| v3 (branch `v3`) | :no_entry_sign: | :no_entry_sign: | :no_entry_sign: | :white_check_mark: | :no_entry_sign: |
+| v4 (branch `master`) | :no_entry_sign: | :no_entry_sign: | :no_entry_sign: | :no_entry_sign: | :white_check_mark: |
 
 When you are using `composer require` and have already declared a dependency to
 `phpunit/phpunit` in your `composer.json` file, Composer should pick latest
@@ -204,7 +205,7 @@ The `$uriOrRequest` value may be
 
 - a string, which will be interpreted as URI
 - an instance of the `Psr\Http\Message\UriInterface` interface
-- an instance of the `Psr\Http\Message\RequestInterface` interface 
+- an instance of the `Psr\Http\Message\RequestInterface` interface
 
 [composer-autoload]: https://getcomposer.org/doc/04-schema.md#autoload-dev
 [json-assert]: https://packagist.org/packages/helmich/phpunit-json-assert