Update ICU to 58.3

- This adds the new Japanese ascension era (Reiwa)
- This updates timezone data to 2019a
- Updated script for git instead of SVN
- Regenerated locale data

intl/icu/source/data/locales/cs.txt

@@ -1,4 +1,4 @@
-// © 2016 and later: Unicode, Inc. and others.
+// © 2016 and later: Unicode, Inc. and others.
 // License & terms of use: http://www.unicode.org/copyright.html#License
 cs{
     AuxExemplarCharacters{"[à ă â å ä ã ā æ ç è ĕ ê ë ē ì ĭ î ï ī ľ ł ñ ò ŏ ô ö ø ō œ ŕ ù ŭ û ü ū ÿ]"}
@@ -2259,6 +2259,7 @@ cs{
                     "Taishō",
                     "Shōwa",
                     "Heisei",
+                    "Reiwa",
                 }
                 narrow{
                     "Taika (645–650)",
@@ -2497,6 +2498,7 @@ cs{
                     "T",
                     "S",
                     "H",
+                    "R",
                 }
                 wide{
                     "Taika (645–650)",
@@ -2735,6 +2737,7 @@ cs{
                     "Taishō",
                     "Shōwa",
                     "Heisei",
+                    "Reiwa",
                 }
             }
         }