Bump version to v3.1.0-rc.1, update homepage URL

Author: milgner

gelf.gemspec

@@ -2,11 +2,11 @@
 # DO NOT EDIT THIS FILE DIRECTLY
 # Instead, edit Jeweler::Tasks in Rakefile, and run 'rake gemspec'
 # -*- encoding: utf-8 -*-
-# stub: gelf 3.0.0 ruby lib
+# stub: gelf 3.1.0-rc.1 ruby lib
 
 Gem::Specification.new do |s|
   s.name = "gelf"
-  s.version = "3.0.0"
+  s.version = "3.1.0-rc.1"
 
   s.required_rubygems_version = Gem::Requirement.new(">= 0") if s.respond_to? :required_rubygems_version=
   s.require_paths = ["lib"]
@@ -44,7 +44,7 @@ Gem::Specification.new do |s|
     "test/test_ruby_sender.rb",
     "test/test_severity.rb"
   ]
-  s.homepage = "http://github.com/Graylog2/gelf-rb"
+  s.homepage = "https://github.com/graylog-labs/gelf-rb"
   s.licenses = ["MIT"]
   s.rubygems_version = "2.5.1"
   s.summary = "Library to send GELF messages to Graylog logging server."