message: update "pptx.colors" to "pptx.SchemeColor"
diff: <meta name="author" content="https://github.com/gitbrent">
  <meta name="website" content="https://github.com/gitbrent/PptxGenJS/">
  <meta name="version" content="3.2.0">
  - <meta name="updated" content="2020-02-04">
  + <meta name="updated" content="2020-03-17">
  <link rel="icon" href="images/favicon-32x32.png" sizes="32x32" type="image/png">
  <link rel="icon" href="images/favicon-16x16.png" sizes="16x16" type="image/png">
  <link rel="icon" href="images/favicon.png">
  + "\n"
  + "slide.addText(\n"
  + " [\n"
  - + " { text:'Did You Know?', options:{ fontSize:48, color:pptx.colors.ACCENT1 } },\n"
  - + " { text:'writeFile() returns a Promise', options:{ fontSize:24, color:pptx.colors.ACCENT6 } },\n"
  - + " { text:'!', options:{ fontSize:24, color:pptx.colors.ACCENT6 } },\n"
  - + " { text:'(pretty cool huh?)', options:{ fontSize:24, color:pptx.colors.ACCENT3 } }\n"
  + + " { text:'Did You Know?', options:{ fontSize:48, color:pptx.SchemeColor.accent1 } },\n"
  + + " { text:'writeFile() returns a Promise', options:{ fontSize:24, color:pptx.SchemeColor.accent6 } },\n"
  + + " { text:'!', options:{ fontSize:24, color:pptx.SchemeColor.accent6 } },\n"
  + + " { text:'(pretty cool huh?)', options:{ fontSize:24, color:pptx.SchemeColor.accent3 } }\n"
  + " ],\n"
  - + " { x:1, y:1, w:'80%', h:3, align:'center', fill:pptx.colors.BACKGROUND2 }\n"
  + + " { x:1, y:1, w:'80%', h:3, align:'center', fill:pptx.SchemeColor.background2 }\n"
  + ");\n"
  + "\n"
  + "pptx.writeFile('PptxGenJS-Sandbox-'+getTimestamp())\n"
  