Add strings for Xiaomi "lock apps" screen.

lib/src/main/res/values/strings.xml

@@ -20,6 +20,11 @@
     <string name="dnkm_xiaomi_dialog_body_old">1. Open the recent apps list (also called the app switcher)\n\n2. Swipe down on the image of this app to show the padlock icon\n\n3. If the padlock is not locked, tap to lock it</string>
     <string name="dnkm_xiaomi_dialog_body_new">1. Open the recent apps list (also called the app switcher)\n\n2. Press and hold the image of this app until the padlock button appears\n\n3. If the padlock is not locked, tap to lock it</string>
 
+    <string name="dnkm_xiaomi_lock_apps_text">Please tap the button below to open the security settings. Tap \"Boost speed\", then tap \"Lock apps\", and make sure this app is set to \"Locked\".</string>
+    <string name="dnkm_xiaomi_lock_apps_button">Open Security Settings</string>
+    <string name="dnkm_xiaomi_lock_apps_help">If this app is not set to \"Locked\" in the \"Lock apps\" screen, it will be unable to run in the background.</string>
+    <string name="dnkm_xiaomi_lock_apps_error_toast">Could not open security settings</string>
+
     <string name="dnkm_got_it">Got it</string>
     <string name="dnkm_help">Help</string>