Fix #99 => Set pie chart colors theme

sample/src/main/java/com/github/aachartmodel/aainfographics/demo/chartcomposer/SpecialChartComposer.kt

@@ -67,6 +67,7 @@ object SpecialChartComposer {
             .backgroundColor("#ffffff")
             .title("LANGUAGE MARKET SHARES JANUARY,2020 TO MAY")
             .subtitle("virtual data")
+            .colorsTheme(arrayOf("#0c9674", "#7dffc0", "#d11b5f", "#facd32", "#ffffa0",))
             .dataLabelsEnabled(true)//是否直接显示扇形图数据
             .yAxisTitle("℃")
             .series(arrayOf(