Corrected Gregorian End Date for 平成 (Heisei) era (#3301)

Changed the end from present to April 30, 2019

Author: digitalcoyote

xml/System.Globalization/JapaneseLunisolarCalendar.xml

@@ -57,7 +57,7 @@ Unlike the <xref:System.Globalization.JapaneseCalendar> class, the `JapaneseLuni
 |GetEra value|Era Name|Era Abbreviation|Gregorian Dates|  
 |------------------|--------------|----------------------|---------------------|  
 |5|令和 (Reiwa)|令和 (R, r)|May 1, 2019 to present|
-|4|平成 (Heisei)|平 (H, h)|January 8, 1989 to present|  
+|4|平成 (Heisei)|平 (H, h)|January 8, 1989 to April 30, 2019|  
 |3|昭和 (Showa)|昭 (S, s)|December 25, 1926 to January 7, 1989|  
 |2|大正 (Taisho)|大 (T, t)|July 30, 1912 to December 24, 1926|  
 |1|明治 (Meiji)|明 (M, m)|September 8, 1868 to July 29, 1912|