Upgrade guard to 2.16.2

After upgrading pry version to 0.13.1, we also need to upgrade guard
to support it.

Gemfile.lock

@@ -516,7 +516,7 @@ GEM
       googleapis-common-protos-types (~> 1.0)
     gssapi (1.2.0)
       ffi (>= 1.0.1)
-    guard (2.15.1)
+    guard (2.16.2)
       formatador (>= 0.2.4)
       listen (>= 2.7, < 4.0)
       lumberjack (>= 1.0.12, < 2.0)
@@ -649,10 +649,9 @@ GEM
       xml-simple
     licensee (8.9.2)
       rugged (~> 0.24)
-    listen (3.1.5)
-      rb-fsevent (~> 0.9, >= 0.9.4)
-      rb-inotify (~> 0.9, >= 0.9.7)
-      ruby_dep (~> 1.2)
+    listen (3.2.1)
+      rb-fsevent (~> 0.10, >= 0.10.3)
+      rb-inotify (~> 0.9, >= 0.9.10)
     locale (2.1.3)
     lockbox (0.3.3)
     lograge (0.11.2)
@@ -664,7 +663,7 @@ GEM
       crass (~> 1.0.2)
       nokogiri (>= 1.5.9)
     lru_redux (1.1.0)
-    lumberjack (1.0.13)
+    lumberjack (1.2.7)
     mail (2.7.1)
       mini_mime (>= 0.1.1)
     marcel (0.3.3)
@@ -899,9 +898,9 @@ GEM
     rainbow (3.0.0)
     raindrops (0.19.1)
     rake (12.3.3)
-    rb-fsevent (0.10.2)
-    rb-inotify (0.9.10)
-      ffi (>= 0.5.0, < 2)
+    rb-fsevent (0.10.4)
+    rb-inotify (0.10.1)
+      ffi (~> 1.0)
     rblineprof (0.3.6)
       debugger-ruby_core_source (~> 1.3)
     rbtrace (0.4.14)
@@ -1020,7 +1019,6 @@ GEM
       nokogiri (>= 1.5.10)
     ruby-statistics (2.1.2)
     ruby2_keywords (0.0.2)
-    ruby_dep (1.5.0)
     ruby_parser (3.13.1)
       sexp_processor (~> 4.9)
     rubyntlm (0.6.2)