Add Japan's Reiwa era

[guimard]

Hello,

could you add new Japan Era ?

--- a/src/webapp/api/scripts/ext/japanese-eras.js
+++ b/src/webapp/api/scripts/ext/japanese-eras.js
@@ -390,6 +390,7 @@
         { startingYear: 1868, japaneseName: '明治', romanizedName: "Meiji" },
         { startingYear: 1912, japaneseName: '大正', romanizedName: "Taishō" },
         { startingYear: 1926, japaneseName: '昭和', romanizedName: "Shōwa" },
-        { startingYear: 1989, japaneseName: '平成', romanizedName: "Heisei" }
+        { startingYear: 1989, japaneseName: '平成', romanizedName: "Heisei" },
+        { startingYear: 2019, japaneseName: '令和', romanizedName: "Reiwa" }
     ]
 );