Check-depends fails for go.mod created by 1.21.x

[mdosch]

Debian Unstable
dh-make-golang/unstable,now 0.6.0-2+b5 amd64

Run dh-make-golang check-depends in a repo of a package which requires go >= 1.21.x, e.g. golang-github-mattn-go-xmpp:

dh-make-golang check-depends
2024/01/13 10:10:26 error while parsing go.mod: go.mod:3: invalid go version '1.21.5': must match format 1.23

[mdosch]

I checked out the repo and compiled dh-make-golang which made no change.
Then I upgraded all dependencies:

go get -u
go mod tidy
go install

Afterwards it worked:

~/build/go/bin/dh-make-golang check-depends
go.mod and d/control are in sync

cat ~/build/dh-make-golang/go.mod 
module github.com/Debian/dh-make-golang

go 1.21

toolchain go1.21.5

require (
	github.com/charmbracelet/glamour v0.6.0
	github.com/google/go-github/v38 v38.1.0
	github.com/gregjones/httpcache v0.0.0-20190611155906-901d90724c79
	github.com/mattn/go-isatty v0.0.20
	golang.org/x/mod v0.14.0
	golang.org/x/net v0.20.0
	golang.org/x/sync v0.6.0
	golang.org/x/tools v0.17.0
	golang.org/x/tools/go/vcs v0.1.0-deprecated
	pault.ag/go/debian v0.16.0
)

require (
	github.com/alecthomas/chroma v0.10.0 // indirect
	github.com/aymanbagabas/go-osc52/v2 v2.0.1 // indirect
	github.com/aymerick/douceur v0.2.0 // indirect
	github.com/dlclark/regexp2 v1.10.0 // indirect
	github.com/google/go-querystring v1.1.0 // indirect
	github.com/gorilla/css v1.0.1 // indirect
	github.com/lucasb-eyer/go-colorful v1.2.0 // indirect
	github.com/mattn/go-runewidth v0.0.15 // indirect
	github.com/microcosm-cc/bluemonday v1.0.26 // indirect
	github.com/muesli/reflow v0.3.0 // indirect
	github.com/muesli/termenv v0.15.2 // indirect
	github.com/olekukonko/tablewriter v0.0.5 // indirect
	github.com/rivo/uniseg v0.4.4 // indirect
	github.com/yuin/goldmark v1.6.0 // indirect
	github.com/yuin/goldmark-emoji v1.0.2 // indirect
	golang.org/x/crypto v0.18.0 // indirect
	golang.org/x/sys v0.16.0 // indirect
	pault.ag/go/topsort v0.1.1 // indirect
)