Add requirement set to manifest for CustomFunctionsRuntime (#117)

Author: akrantz

manifest.xml

@@ -22,6 +22,11 @@
     <SourceLocation DefaultValue="https://localhost:3000/taskpane.html"/>
   </DefaultSettings>
   <Permissions>ReadWriteDocument</Permissions>
+  <Requirements>
+    <Sets DefaultMinVersion="1.1">
+        <Set Name="CustomFunctionsRuntime" MinVersion="1.1"/>
+    </Sets>
+  </Requirements>  
   <VersionOverrides xmlns="http://schemas.microsoft.com/office/taskpaneappversionoverrides" xsi:type="VersionOverridesV1_0">
     <Hosts>
       <Host xsi:type="Workbook">