Update bundler-audit and brakeman (#4740)

Gemfile.lock

@@ -74,13 +74,13 @@ GEM
       debug_inspector (>= 0.0.1)
     bootsnap (1.1.2)
       msgpack (~> 1.0)
-    brakeman (3.6.2)
+    brakeman (3.7.2)
     browser (2.4.0)
     builder (3.2.3)
     bullet (5.5.1)
       activesupport (>= 3.0.0)
       uniform_notifier (~> 1.10.0)
-    bundler-audit (0.5.0)
+    bundler-audit (0.6.0)
       bundler (~> 1.2)
       thor (~> 0.18)
     capistrano (3.8.2)
@@ -468,7 +468,7 @@ GEM
     temple (0.8.0)
     terminal-table (1.8.0)
       unicode-display_width (~> 1.1, >= 1.1.1)
-    thor (0.19.4)
+    thor (0.20.0)
     thread (0.2.2)
     thread_safe (0.3.6)
     tilt (2.0.8)