Suppress lint error about elevation

Author: ajungg

ui/src/main/res/values/styles.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
-<resources>
+<resources xmlns:tools="http://schemas.android.com/tools">
 
     <style name="SnabbleTheme" parent="@style/Theme.AppCompat.Light">
         <item name="colorPrimary">@color/snabble_primaryColor</item>
@@ -24,14 +24,14 @@
         <item name="android:textColor">@color/snabble_textColorLight</item>
         <item name="android:background">@drawable/ic_button</item>
         <item name="backgroundTint">@color/snabble_primaryColorAction</item>
-        <item name="android:elevation">1dp</item>
+        <item name="android:elevation" tools:targetApi="lollipop">1dp</item>
     </style>
 
     <style name="SnabbleButtonWhite" parent="@style/Widget.AppCompat.Button.Borderless">
         <item name="android:textColor">@color/snabble_textColorDark</item>
         <item name="android:background">@drawable/ic_button</item>
         <item name="backgroundTint">#ffffff</item>
-        <item name="android:elevation">1dp</item>
+        <item name="android:elevation" tools:targetApi="lollipop">1dp</item>
     </style>
 
     <style name="SnabbleEditText" parent="@style/Widget.AppCompat.EditText">