Update zoneinfo files to 2019a. (#100)

Author: devbww

src/tzfile.h

@@ -33,6 +33,9 @@
 #define TZDEFRULES	"posixrules"
 #endif /* !defined TZDEFRULES */
 
+
+/* See Internet RFC 8536 for more details about the following format.  */
+
 /*
 ** Each file begins with. . .
 */

testdata/version

@@ -1 +1 @@
-2018i
+2019a