Compatibiliy for symfony 5

[Khatib-Abbas]

Hi, When i want to install this bundle i got this errors Thanks in advance for your help

Problem 1

• kreait/firebase-bundle 1.6.1 requires symfony/dependency-injection ^2.8.50|^3.4.26|^4.1.12 -> no matching package found.
• kreait/firebase-bundle 1.6.0 requires symfony/dependency-injection ^2.8|^3.4|^4.0 -> no matching package found.
• Installation request for kreait/firebase-bundle ^1.6 -> satisfiable by kreait/firebase-bundle[1.6.0, 1.6.1].

Potential causes:

• A typo in the package name
• The package is not available in a stable-enough version according to your minimum-stability setting see https://getcomposer.org/doc/04-schema.md#minimum-stability for more details.
• It's a private package and you forgot to add a custom repository to find it

Read https://getcomposer.org/doc/articles/troubleshooting.md for further common problems.

[jeromegamez]

I‘ll update the dependency constraints soon, but I‘m also open for a pull request 😅

[jeromegamez]

I just released 1.7.0, please let me know if something doesn't work after the update. 🤞