symfony/symfony — pull request #12543 by nicolas-grekas (2014-11-21 19:25:22+00:00)
Title: Allow ~3.0 deps

| Q | A
| ------------- | ---
| Bug fix? | no
| New feature? | no
| BC breaks? | no
| Deprecations? | no
| Tests pass? | yes
| Fixed tickets | -
| License | MIT
| Doc PR | -

Thanks to our BC promise, we can (and should ensure) that 3.0 components work when mixed with 2.x ones.
This PR allows mixing, while #12542 will allow verifying that it works effectively.