update bullet to use it with active record 7.1

Gemfile.lock

@@ -85,7 +85,7 @@ GEM
     bleib (0.0.12)
     brakeman (5.2.1)
     builder (3.2.4)
-    bullet (7.0.7)
+    bullet (7.1.6)
       activesupport (>= 3.0.0)
       uniform_notifier (~> 1.11)
     byebug (11.1.3)
@@ -102,7 +102,7 @@ GEM
       activesupport
     choice (0.2.0)
     coderay (1.1.3)
-    concurrent-ruby (1.2.2)
+    concurrent-ruby (1.3.3)
     countries (5.4.0)
       unaccent (~> 0.3)
     crack (0.4.5)
@@ -137,7 +137,7 @@ GEM
     hashdiff (1.0.1)
     hirb (0.7.3)
     httpclient (2.8.3)
-    i18n (1.14.1)
+    i18n (1.14.5)
       concurrent-ruby (~> 1.0)
     json-jwt (1.15.3)
       activesupport (>= 4.2)
@@ -160,7 +160,7 @@ GEM
     maxmind-db (1.1.1)
     method_source (1.0.0)
     mini_mime (1.1.2)
-    minitest (5.18.1)
+    minitest (5.23.1)
     mocha (2.0.2)
       ruby2_keywords (>= 0.0.5)
     mysql2 (0.5.5)