Revert "Increase target API level to 29 (Android 10.0)"

This reverts commit f0abf9b537c2a3d8fb67454ff37ea1f57400eb5d.

See #194

app/build.gradle

@@ -8,7 +8,7 @@ android {
         versionCode 29
         versionName "11.3a"
         minSdkVersion 14
-        targetSdkVersion 29
+        targetSdkVersion 28
     }
     buildTypes {
         release {

love/build.gradle

@@ -24,7 +24,6 @@ android {
             // libraries Gradle should build and package with your APK.
             abiFilters 'armeabi-v7a', 'arm64-v8a'
         }
-        targetSdkVersion 29
     }
     buildTypes {
         release {