Update README.md

v1.5

Author: llaville

README.md

@@ -7,6 +7,7 @@ Here are the links to the documentation for versions that are still supported :
 - [SARIF PHP SDK 1.2](https://llaville.github.io/sarif-php-sdk/1.2/)
 - [SARIF PHP SDK 1.3](https://llaville.github.io/sarif-php-sdk/1.3/)
 - [SARIF PHP SDK 1.4](https://llaville.github.io/sarif-php-sdk/1.4/)
+- [SARIF PHP SDK 1.5](https://llaville.github.io/sarif-php-sdk/1.5/)
 
 Full documentation may be found in `docs` folder into this repository, and may be read online without to do anything else.