crash on build feed xml in some cases

[Rpsl]

panic: runtime error: slice bounds out of range [:4000] with capacity 3392

goroutine 68 [running]:
github.com/eduncan911/podcast.(*Item).AddSummary(...)
	/path/go/pkg/mod/github.com/eduncan911/podcast@v1.3.0/item.go:93
github.com/mxpv/podsync/pkg/feed.Build(0x1773b20, 0xc00018a0c0, 0xc005912420, 0xc0001c20c0, 0x7e66840, 0xc005646520, 0x0, 0x0, 0x0)
	/path/go/src/github.com/rpsl/podsync/pkg/feed/build.go:81 +0x1373
main.(*Updater).buildXML(0xc0000302c0, 0x1773b20, 0xc00018a0c0, 0xc0001c20c0, 0x0, 0x0)
	/path/go/src/github.com/rpsl/podsync/cmd/podsync/updater.go:246 +0x164
main.(*Updater).Update(0xc0000302c0, 0x1773b20, 0xc00018a0c0, 0xc0001c20c0, 0x1, 0x0)
	/path/go/src/github.com/rpsl/podsync/cmd/podsync/updater.go:62 +0x38a
main.main.func1(0x0, 0x0)
	/path/go/src/github.com/rpsl/podsync/cmd/podsync/main.go:135 +0x17d
golang.org/x/sync/errgroup.(*Group).Go.func1(0xc0001823f0, 0xc000030300)
	/path/go/pkg/mod/golang.org/x/sync@v0.0.0-20190423024810-112230192c58/errgroup/errgroup.go:57 +0x59
created by golang.org/x/sync/errgroup.(*Group).Go
	/path/go/pkg/mod/golang.org/x/sync@v0.0.0-20190423024810-112230192c58/errgroup/errgroup.go:54 +0x66
exit status 2

It's going on some Items with description written on non latin utf8 chars.

it's was be fixed in version 1.3.1 of eduncan911/podcast

need to update dependence