Dependency on a specific version of nikic/php-parser

Your package has dependency on `nikic/php-parser: 3.0.6`. But my project already installed php-parser but 3.1.1 version. For this reason I can't install `soft-mocks`, if I try I got next error:
```
Problem 1
- Can only install one of: nikic/php-parser[v3.0.6, v3.1.1].
- Can only install one of: nikic/php-parser[v3.1.1, v3.0.6].
- Can only install one of: nikic/php-parser[v3.0.6, v3.1.1].
- badoo/soft-mocks 1.3.0 requires nikic/php-parser 3.0.6 -> satisfiable by nikic/php-parser[v3.0.6].
- Installation request for badoo/soft-mocks ^1.3 -> satisfiable by badoo/soft-mocks[1.3.0].
- Installation request for nikic/php-parser (locked at v3.1.1, required as ^3.0.6) -> satisfiable by nikic/php-parser[v3.1.1].
```
Is there a reason to declare a dependency on a specific version? Maybe you need to write
"nikic/php-parser": "^3.0.6" in your `composer.json`?

Inspect composer.json and the nikic/php-parser requirement first. Check whether the package supports the requested compatible version range, then verify the dependency resolution with Composer using php-parser 3.1.1. Done means soft-mocks can install alongside that version without the reported conflict.

Written by the indexing model from the issue text.