Set version to 27.2.0.

Author: pocmo

.buildconfig.yml

@@ -1,4 +1,4 @@
-componentsVersion: 29.0.0
+componentsVersion: 27.2.0
 projects:
   concept-awesomebar:
     path: components/concept/awesomebar

samples/browser/src/main/java/org/mozilla/samples/browser/MigrationService.kt

@@ -0,0 +1,13 @@
+package org.mozilla.samples.browser
+
+import mozilla.components.support.migration.AbstractMigrationService
+import mozilla.components.support.migration.state.MigrationStore
+import org.mozilla.samples.browser.ext.components
+
+/**
+ * Something.
+ */
+class MigrationService : AbstractMigrationService() {
+    override val migrator by lazy { components.migrator }
+    override val store: MigrationStore by lazy { components.migrationStore }
+}