Updates veggieseasons to Dart 2.3, adds some minor UI updates (#88)

veggieseasons/pubspec.lock

@@ -21,7 +21,7 @@ packages:
       name: async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.8"
+    version: "2.1.0"
   boolean_selector:
     dependency: transitive
     description:
@@ -117,7 +117,7 @@ packages:
       name: matcher
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.12.3+1"
+    version: "0.12.5"
   meta:
     dependency: transitive
     description:
@@ -138,7 +138,7 @@ packages:
       name: pedantic
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.4.0"
+    version: "1.5.0"
   petitparser:
     dependency: transitive
     description:
@@ -152,7 +152,7 @@ packages:
       name: quiver
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.1"
+    version: "2.0.2"
   scoped_model:
     dependency: "direct main"
     description:
@@ -178,7 +178,7 @@ packages:
       name: source_span
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.5.4"
+    version: "1.5.5"
   stack_trace:
     dependency: transitive
     description:
@@ -192,7 +192,7 @@ packages:
       name: stream_channel
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.6.8"
+    version: "2.0.0"
   string_scanner:
     dependency: transitive
     description:
@@ -213,7 +213,7 @@ packages:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.2.2"
+    version: "0.2.4"
   typed_data:
     dependency: transitive
     description:
@@ -243,5 +243,5 @@ packages:
     source: hosted
     version: "2.1.15"
 sdks:
-  dart: ">=2.1.0 <3.0.0"
+  dart: ">=2.3.0-dev <3.0.0"
   flutter: ">=0.1.4 <2.0.0"