[SKIP CI] Add string for EOL update check message

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

@@ -710,6 +710,7 @@
     <!--UpdateCheck-->
     <string name="update_check_confirm">Download</string>
     <string name="update_check_ignore">Ignore</string>
+    <string name="update_check_eol">This Android version is no longer supported</string>
     <string name="update_check_no_new_updates">No new updates available</string>
     <string name="update_check_look_for_updates">Searching for updates…</string>