localize version requirement string

AndroidManifest.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="org.fox.ttrss"
-    android:versionCode="154"
+    android:versionCode="155"
     android:versionName="1.4.5" >
 
     <uses-sdk

res/values/strings.xml

@@ -188,4 +188,5 @@
     <string name="headlines_unread">Unread</string>
     <string name="article_img_open">Open image</string>
     <string name="article_img_share">Share image</string>
+    <string name="requires_api5">Requires version 1.7.6</string>
 </resources>

res/xml/preferences.xml

@@ -96,7 +96,7 @@
         <CheckBoxPreference
             android:defaultValue="false"
             android:key="oldest_first"
-            android:summary="Requires version 1.7.6"
+            android:summary="@string/requires_api5"
             android:title="@string/offline_oldest_first" />
         
     </PreferenceCategory>