<?xml version="1.0" encoding="UTF-8"?>
<plugin xmlns="http://apache.org/cordova/ns/plugins/1.0"
           id="cordova-plugin-sketch"
      version="0.1.0">

    <name>Sketch</name>
    <description>Cordova Sketch Plugin</description>
    <license>Apache 2.0</license>
    <keywords>cordova,sketch,signature,draw</keywords>

    <js-module src="www/sketch.js" name="sketch">
        <clobbers target="navigator.sketch" />
    </js-module>

    <!-- windows -->
    <platform name="windows">
        <js-module src="src/windows/sketchProxy.js" name="SketchProxy">
            <merges target="" />
        </js-module>
        <asset src="www/css/cordova-plugin-sketch.css" target="cordova-plugin-sketch/css/cordova-plugin-sketch.css" />
        <asset src="www/css/program.css" target="cordova-plugin-sketch/css/program.css" />
        <asset src="www/images/Erase.cur" target="cordova-plugin-sketch/images/Erase.cur" />
        <asset src="www/images/Select.png" target="cordova-plugin-sketch/images/Select.png" />
        <asset src="www/canvasHtml.js" target="cordova-plugin-sketch/canvasHtml.js" />
        <asset src="www/program.js" target="cordova-plugin-sketch/program.js" />    </platform>

    </plugin>

<?xml version="1.0" encoding="UTF-8"?>
<plugin xmlns="http://apache.org/cordova/ns/plugins/1.0"
           id="cordova-plugin-sketch"
      version="0.1.0">

    <name>Sketch</name>
    <description>Cordova Sketch Plugin</description>
    <license>Apache 2.0</license>
    <keywords>cordova,sketch,signature,draw</keywords>

    <js-module src="www/sketch.js" name="sketch">
        <clobbers target="navigator.sketch" />
    </js-module>

    <!-- windows -->
    <platform name="windows">
        <js-module src="src/windows/sketchProxy.js" name="SketchProxy">
            <merges target="" />
        </js-module>
        <asset src="www/css/cordova-plugin-sketch.css" target="cordova-plugin-sketch/css/cordova-plugin-sketch.css" />
        <asset src="www/css/program.css" target="cordova-plugin-sketch/css/program.css" />
        <asset src="www/images/Erase.cur" target="cordova-plugin-sketch/images/Erase.cur" />
        <asset src="www/images/Select.png" target="cordova-plugin-sketch/images/Select.png" />
        <asset src="www/canvasHtml.js" target="cordova-plugin-sketch/canvasHtml.js" />
        <asset src="www/program.js" target="cordova-plugin-sketch/program.js" />    
        <config-file target="package.appxmanifest" parent="/Package/Capabilities" versions="8.1.0">
            <Capability Name="picturesLibrary" />
        </config-file>

    </platform>

    </plugin>

Add picture library capability requirement
Add picture library capability requirement