release/1.2.1: update version code & version name

Author: zuevval

app/build.gradle

@@ -26,8 +26,8 @@ android {
         applicationId "com.github.braillesystems.learnbraille"
         minSdkVersion 19
         targetSdkVersion 29
-        versionCode 14
-        versionName "1.2.0"
+        versionCode 15
+        versionName "1.2.1"
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
         vectorDrawables.useSupportLibrary = true
         multiDexEnabled = true