update gems; version bump

Gemfile.lock

 PATH
   remote: .
   specs:
-    steem-ruby (0.9.0)
+    steem-ruby (0.9.1)
       bitcoin-ruby (~> 0.0, >= 0.0.18)
       ffi (~> 1.9, >= 1.9.23)
       hashie (~> 3.5, >= 3.5.7)
@@ -18,8 +18,8 @@ GEM
     coderay (1.1.2)
     crack (0.4.3)
       safe_yaml (~> 1.0.0)
-    docile (1.3.0)
-    ffi (1.9.23)
+    docile (1.3.1)
+    ffi (1.9.25)
     hashdiff (0.3.7)
     hashie (3.5.7)
     json (2.1.0)
@@ -28,8 +28,8 @@ GEM
       little-plugger (~> 1.1)
       multi_json (~> 1.10)
     method_source (0.9.0)
-    minitest (5.10.3)
-    minitest-line (0.6.4)
+    minitest (5.11.3)
+    minitest-line (0.6.5)
       minitest (~> 5.0)
     minitest-proveit (1.0.0)
       minitest (> 5, < 7)
@@ -46,11 +46,11 @@ GEM
       simplecov-html (~> 0.10.0)
     simplecov-html (0.10.2)
     vcr (4.0.0)
-    webmock (3.3.0)
+    webmock (3.4.2)
       addressable (>= 2.3.6)
       crack (>= 0.3.2)
       hashdiff
-    yard (0.9.12)
+    yard (0.9.14)
 
 PLATFORMS
   ruby

lib/steem/version.rb

 module Steem
-  VERSION = '0.9.0'
+  VERSION = '0.9.1'
   AGENT_ID = "steem-ruby/#{VERSION}"
 end