feat: add alert

examples/gallery/lib/main.dart

@@ -97,6 +97,7 @@ class _MyHomePageState extends State<MyHomePage> {
             StateLabel(StateLabelStatus.issueOpened),
             StateLabel(StateLabelStatus.issueClosed),
             StateLabel(StateLabelStatus.pullMerged),
+            Alert('Flash message goes here.'),
             BranchName('a_new_feature_branch'),
             Text(
               'You have pushed the button this many times:',

lib/primer.dart

@@ -1,3 +1,5 @@
+export 'src/utils.dart';
 export 'src/label.dart';
 export 'src/colors.dart';
 export 'src/branch_name.dart';
+export 'src/alert.dart';

lib/src/alert.dart

@@ -0,0 +1,26 @@
+import 'package:flutter/widgets.dart';
+import 'colors.dart';
+import 'utils.dart';
+
+class Alert extends StatelessWidget {
+  final String text;
+  final PrimerTheme theme;
+
+  Alert(this.text, {this.theme});
+
+  @override
+  Widget build(BuildContext context) {
+    return Container(
+      padding: EdgeInsets.all(16),
+      decoration: BoxDecoration(
+        color: PrimerColors.blue100,
+        borderRadius: BorderRadius.all(Radius.circular(3)),
+        border: Border.all(color: Color(0x1b1f2326), width: 1),
+      ),
+      child: Text(
+        text,
+        style: TextStyle(color: PrimerColors.blue800),
+      ),
+    );
+  }
+}

lib/src/label.dart

@@ -1,16 +1,10 @@
 import 'package:flutter/widgets.dart';
 import 'octicons.dart';
 import 'colors.dart';
+import 'utils.dart';
 
 const openGreen = Color(0xff2cbe4e);
 
-enum PrimerTheme {
-  primary,
-  warn,
-  error,
-  success,
-}
-
 Map<PrimerTheme, Color> colorMap = {
   PrimerTheme.primary: PrimerColors.blue500,
 };

lib/src/utils.dart

@@ -0,0 +1,6 @@
+enum PrimerTheme {
+  primary,
+  warn,
+  error,
+  success,
+}