cleaner ci

frontend/android/app/build.gradle

@@ -7,7 +7,7 @@ plugins {
 }
 
 def localProperties = new Properties()
-def localPropertiesFile = rootProject.file('local.properties')
+def localPropertiesFile = rootProject.file('secrets.properties')
 if (localPropertiesFile.exists()) {
     localPropertiesFile.withReader('UTF-8') { reader ->
         localProperties.load(reader)
@@ -54,6 +54,9 @@ android {
         targetSdkVersion flutter.targetSdkVersion
         versionCode flutterVersionCode.toInteger()
         versionName flutterVersionName
+        // Placeholders of keys that are replaced by the build system.
+        manifestPlaceholders += [MAPS_API_KEY: "some value"]
+
     }
 
     buildTypes {

frontend/android/fallback.properties

@@ -0,0 +1 @@
+MAPS_API_KEY=Key