allow for parallel_total_shards of -1 (#35)

* allow for parallel_total_shards of -1

* bump TargetRubyVersion for rubocop to 2.2

* allow for parallel_total_shards to be > 1 or exactly -1

* v1.14.1

.rubocop.yml

@@ -7,4 +7,4 @@ RSpec/InstanceVariable:
     - spec/lib/percy/client/environment_spec.rb
 
 AllCops:
-  TargetRubyVersion: 2.1
+  TargetRubyVersion: 2.2

lib/percy/client/builds.rb

@@ -13,9 +13,9 @@ def create_build(repo, options = {})
         parallel_total_shards = options[:parallel_total_shards] \
           || Percy::Client::Environment.parallel_total_shards
 
-        # Only pass parallelism data if it all exists and there is more than 1 shard.
+        # Only pass parallelism data if it all exists and there is more than 1, or exactly -1 shard.
         in_parallel_environment = parallel_nonce && \
-          parallel_total_shards && parallel_total_shards > 1
+          parallel_total_shards && parallel_total_shards > 1 || parallel_total_shards == -1
 
         unless in_parallel_environment
           parallel_nonce = nil

lib/percy/client/version.rb

@@ -1,5 +1,5 @@
 module Percy
   class Client
-    VERSION = '1.14.0'.freeze
+    VERSION = '1.14.1'.freeze
   end
 end