Merge pull request #2087 from corona-warn-app/feature/api_downgrade

API downgrade to 29

Corona-Warn-App/build.gradle

@@ -38,13 +38,13 @@ android {
     println("Current VERSION_PATCH: ${VERSION_PATCH}")
     println("Current VERSION_BUILD: ${VERSION_BUILD}")
 
-    compileSdkVersion 30
+    compileSdkVersion 29
     buildToolsVersion "29.0.3"
 
     defaultConfig {
         applicationId 'de.rki.coronawarnapp'
         minSdkVersion 23
-        targetSdkVersion 30
+        targetSdkVersion 29
 
         ndkVersion "21.2.6472646"