Add Vietnamese translation for Installer++

Author: ThePrimalPea

app/src/main/res/values-vi/strings.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <string name="app_name" translatable="false">Installer++</string>
+    <string name="IPP_info_version">Phiên bản</string>
+    <string name="IPP_info_package">Gói</string>
+    <string name="IPP_info_user">Người dùng</string>
+    <string name="IPP_res_inject_success" translatable="false">Resources injection success</string>
+</resources>