relax rails dependency

[kimsuelim]

The dependencies for Rails 5.1 are too strict. This is going to require a new release when > 5.1.0 is released

[benlovell]

Thanks, I'll cut a release.

[rhuppert]

I'm using Rails 5.0.2. Lograge 0.5.0 was installed and when I did a bundle update, it reverted to 0.3.6 without a version specifier.

[rhuppert]

I'm now using Rails 5.0.3 and attempted to update from lograge 0.5.0.
Without designating a version, it reverts to 0.4.1
When "~> 0.5.1" is specified, I get

Bundler could not find compatible versions for gem "actionpack":
  In Gemfile:
    lograge (~> 0.5.1) was resolved to 0.5.1, which depends on
      actionpack (< 5.2, >= 4)

    rails (= 5.0.3) was resolved to 5.0.3, which depends on
      actionpack (= 5.0.3)

    lograge (~> 0.5.1) was resolved to 0.5.1, which depends on
      railties (< 5.2, >= 4) was resolved to 5.0.0.1, which depends on
        actionpack (= 5.0.0.1)

When I specify '= 0.5.1' , ActionPack resolves to 4.2.7.

I've spent some time looking and I do not understand why railties resolves to 5.0.0.1 instead of 5.0.3. I must be missing something or maybe it's a Bundler issue.

Would changing the dependencies from '< 5.2' to '< 5.2.0' resolve the issue? I would do a pull request, but I'm unclear what I would change.