Update version to 1.12-2

hajimehoshi · hajimehoshi · commit c26baa66a779 · 2019-05-01T01:34:44.000+09:00
Introducing `syscall/js` (#899) is so significant that we update the version.
diff --git a/compiler/version_check.go b/compiler/version_check.go
@@ -6,4 +6,4 @@ package compiler
 const ___GOPHERJS_REQUIRES_GO_VERSION_1_12___ = true
 
 // Version is the GopherJS compiler version string.
-const Version = "1.12-1"
+const Version = "1.12-2"
