Updates samples for latest beta release of the Flutter SDK (#492)

* Updating for beta release

* Re-adding pub get to Flutter travis script

provider_shopper/pubspec.lock

@@ -1,27 +1,13 @@
 # Generated by pub
 # See https://dart.dev/tools/pub/glossary#lockfile
 packages:
-  archive:
-    dependency: transitive
-    description:
-      name: archive
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "2.0.13"
-  args:
-    dependency: transitive
-    description:
-      name: args
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.6.0"
   async:
     dependency: transitive
     description:
       name: async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.4.1"
+    version: "2.4.2"
   boolean_selector:
     dependency: transitive
     description:
@@ -29,6 +15,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.0.0"
+  characters:
+    dependency: transitive
+    description:
+      name: characters
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.0"
   charcode:
     dependency: transitive
     description:
@@ -36,27 +29,27 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.1.3"
+  clock:
+    dependency: transitive
+    description:
+      name: clock
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.1"
   collection:
     dependency: transitive
     description:
       name: collection
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.14.12"
-  convert:
+    version: "1.14.13"
+  fake_async:
     dependency: transitive
     description:
-      name: convert
+      name: fake_async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.1"
-  crypto:
-    dependency: transitive
-    description:
-      name: crypto
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "2.1.4"
+    version: "1.1.0"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -67,20 +60,13 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
-  image:
-    dependency: transitive
-    description:
-      name: image
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "2.1.12"
   matcher:
     dependency: transitive
     description:
       name: matcher
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.12.6"
+    version: "0.12.8"
   meta:
     dependency: transitive
     description:
@@ -101,7 +87,7 @@ packages:
       name: path
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.6.4"
+    version: "1.7.0"
   pedantic:
     dependency: "direct dev"
     description:
@@ -109,13 +95,6 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.9.0"
-  petitparser:
-    dependency: transitive
-    description:
-      name: petitparser
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "2.4.0"
   provider:
     dependency: "direct main"
     description:
@@ -123,13 +102,6 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "4.1.0"
-  quiver:
-    dependency: transitive
-    description:
-      name: quiver
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "2.1.3"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -148,7 +120,7 @@ packages:
       name: stack_trace
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.9.3"
+    version: "1.9.5"
   stream_channel:
     dependency: transitive
     description:
@@ -176,14 +148,14 @@ packages:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.2.15"
+    version: "0.2.17"
   typed_data:
     dependency: transitive
     description:
       name: typed_data
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.6"
+    version: "1.2.0"
   vector_math:
     dependency: transitive
     description:
@@ -191,13 +163,6 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.0.8"
-  xml:
-    dependency: transitive
-    description:
-      name: xml
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "3.6.1"
 sdks:
-  dart: ">=2.7.0 <3.0.0"
+  dart: ">=2.9.0-14.0.dev <3.0.0"
   flutter: ">=1.17.0"