Embed fallback tzdata (#415)

## What was changed
Embed time zone database in case platform database can't be found.

## Why?
This ensures time zones are always available, even on Windows which does
not supply a time zone database (at least in a format that Go
understands).

cmd/temporal/main.go

@@ -7,6 +7,9 @@ import (
 	// Load sqlite storage driver
 	_ "go.temporal.io/server/common/persistence/sql/sqlplugin/sqlite"
 
+	// Embed time zone database as a fallback if platform database can't be found
+	_ "time/tzdata"
+
 	"github.com/temporalio/cli/app"
 )