fix android sign issue

android/app/build.gradle

@@ -61,7 +61,7 @@ android {
     defaultConfig {
         // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
         applicationId "com.akuhome.recook"
-        minSdkVersion 24
+        minSdkVersion 21
         targetSdkVersion 28
         versionCode flutterVersionCode.toInteger()
         versionName flutterVersionName
@@ -97,14 +97,14 @@ android {
         }
     }
 
-    signingConfigs {
+    signingConfigs {        
         debug {
             keyAlias 'alias'
             keyPassword 'recook'
             // storeFile file('/Users/nansi/Desktop/Flutter/Project/recook/jks/recook.keystore')
             storeFile file('../../jks/recook.keystore');
             storePassword 'recook'
-        }
+        } 
     }
 
     configurations.all {

android/build.gradle

@@ -1,5 +1,6 @@
 buildscript {
     ext.kotlin_version = '1.3.10'
+    ext.flutterFFmpegPackage = 'min-lts'
     repositories {
         google()
         jcenter()

pubspec.yaml

@@ -2,7 +2,7 @@ name: recook
 description: Recook Market App.
 publish_to: "none"
 
-version: 1.2.15-dev+178
+version: 1.2.16+179
 
 # sdk min version to 2.2.2
 # to support ... feature