update go to 1.21 in go.mod

[dmitris]

PR updates the go directive to go 1.21 from go 1.18 in go.mod file. Both direct dependencies contain that version in their respective go.mod files:

• https://github.com/googleapis/go-genproto/blob/796eee8c2d537a6e5c8de22908f4facea945ebde/googleapis/api/go.mod#L3
• https://github.com/protocolbuffers/protobuf-go/blob/v1.35.1/go.mod#L3

[kommendorkapten]

What problem are you trying to solve with this? The go version directive is a bit confusing, but IIRC it refers to the minimum version need to to compile the module.

if we are bumping the version to > 1.22, we must set the patch version too, as it won't work otherwise (i.e. 1.22.0).

[dmitris]

What problem are you trying to solve with this? The go version directive is a bit confusing, but IIRC it refers to the minimum version need to to compile the module.

Currently it is impossible to execute any go commands in the repository such as go list ./...:

$ go mod tidy && git diff
diff --git a/go.mod b/go.mod
index 0ac4c88..b66c03f 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,8 @@
 module github.com/sigstore/protobuf-specs

-go 1.18
+go 1.21
+
+toolchain go1.23.2

 require (
        google.golang.org/genproto/googleapis/api v0.0.0-20230726155614-23370e0ffb3e

I'm surprised the CI doesn't have any complaints - maybe we should add some check that would reveal problems like this one?

if we are bumping the version to > 1.22, we must set the patch version too, as it won't work otherwise (i.e. 1.22.0).

👍 I changed the directive to 1.22.0.