Roll Observatory deps (charted -> ^0.3.0)

packages/dart_style/test/splitting/members.unit

 40 columns                              |
 >>> prefers to wrap at => before params
 class Foo {
   Stream methodName(AssetId id) => methodBodyHereItIs;
 }
 <<<
 class Foo {
   Stream methodName(AssetId id) =>
       methodBodyHereItIs;
+}
+>>> can split on getter
+class Foo {
+  VeryLongTypeAnnotation get veryLongGetter => null;
+}
+<<<
+class Foo {
+  VeryLongTypeAnnotation
+      get veryLongGetter => null;
+}
+>>> can split on setter
+class Foo {
+  VeryLongTypeAnnotation set veryLongSetter(v) {}
+}
+<<<
+class Foo {
+  VeryLongTypeAnnotation
+      set veryLongSetter(v) {}
 }