Fix not loading timezones on all operating systems

go.mod

@@ -17,6 +17,7 @@
 module code.vikunja.io/api
 
 require (
+	4d63.com/tz v1.1.0
 	code.vikunja.io/web v0.0.0-20200618164749-a5f3d450d39a
 	gitea.com/xorm/xorm-redis-cache v0.2.0
 	github.com/alecthomas/template v0.0.0-20190718012654-fb15b899a751

go.sum

@@ -1,3 +1,7 @@
+4d63.com/embedfiles v0.0.0-20190311033909-995e0740726f h1:oyYjGRBNq1TxAIG8aHqtxlvqUfzdZf+MbcRb/oweNfY=
+4d63.com/embedfiles v0.0.0-20190311033909-995e0740726f/go.mod h1:HxEsUxoVZyRxsZML/S6e2xAuieFMlGO0756ncWx1aXE=
+4d63.com/tz v1.1.0 h1:Hi58WbeFjiUH4XOWuCpl5iSzuUuw1axZzTqIfMKPKrg=
+4d63.com/tz v1.1.0/go.mod h1:SHGqVdL7hd2ZaX2T9uEiOZ/OFAUfCCLURdLPJsd8ZNs=
 cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
 cloud.google.com/go v0.34.0 h1:eOI3/cP2VTU6uZLDYAoic+eyzzB9YyGmJ7eIjl8rOPg=
 cloud.google.com/go v0.34.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=

pkg/config/config.go

@@ -26,6 +26,7 @@ import (
 	"strings"
 	"time"
 
+	"4d63.com/tz"
 	"github.com/spf13/viper"
 )
 
@@ -159,7 +160,7 @@ var timezone *time.Location
 // it way easier, especially when testing.
 func GetTimeZone() *time.Location {
 	if timezone == nil {
-		loc, err := time.LoadLocation(ServiceTimeZone.GetString())
+		loc, err := tz.LoadLocation(ServiceTimeZone.GetString())
 		if err != nil {
 			fmt.Printf("Error parsing time zone: %s", err)
 			os.Exit(1)