chore: upgrade app version (#1961)

Author: CloudyPadmal

app/build.gradle

@@ -13,8 +13,8 @@ android {
         applicationId "io.pslab"
         minSdkVersion rootProject.ext.minSdkVersion
         targetSdkVersion rootProject.ext.targetSdkVersion
-        versionCode 19
-        versionName "2.0.18"
+        versionCode 20
+        versionName "2.0.19"
         multiDexEnabled true
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
     }