jsonexample maintenance (#150)

* jsonexample maintenance

* formatting

jsonexample/pubspec.lock

@@ -42,7 +42,7 @@ packages:
       name: build
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.6"
+    version: "1.2.0"
   build_config:
     dependency: transitive
     description:
@@ -56,28 +56,28 @@ packages:
       name: build_daemon
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.0"
+    version: "2.1.0"
   build_resolvers:
     dependency: transitive
     description:
       name: build_resolvers
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.0.7"
+    version: "1.1.1"
   build_runner:
     dependency: "direct dev"
     description:
       name: build_runner
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.6.8"
+    version: "1.7.1"
   build_runner_core:
     dependency: transitive
     description:
       name: build_runner_core
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "3.1.0"
+    version: "4.1.0"
   built_collection:
     dependency: "direct main"
     description:
@@ -140,7 +140,7 @@ packages:
       name: crypto
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.2"
+    version: "2.1.3"
   csslib:
     dependency: transitive
     description:
@@ -199,7 +199,7 @@ packages:
       name: html
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.14.0+2"
+    version: "0.14.0+3"
   http:
     dependency: transitive
     description:
@@ -456,6 +456,6 @@ packages:
       name: yaml
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.16"
+    version: "2.2.0"
 sdks:
   dart: ">=2.5.0 <3.0.0"