Remove psr/log dependency.

Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - kmd/logviewer dev-master requires psr/log dev-master -> satisfiable by psr/log[dev-master].
    - kmd/logviewer dev-master requires psr/log dev-master -> satisfiable by psr/log[dev-master].
    - Conclusion: don't install psr/log dev-master
    - Installation request for kmd/logviewer dev-master -> satisfiable by kmd/logviewer[dev-master].