feat: update golang.org/x/exp dependency and fix breaking changes

[krostar]

Hello!

Since this update of the golang/exp project, the slices package has a breaking change.

The commit message of the golang/exp package, introducing the regression, is explicit about it.

Note that this changes some of the sorting functions to use a
comparison function rather than a less function. We don't promise
backward compatibility in x/exp packages.

As far as I know, there is no urgency to update the golang/exp package version.

Step to reproduce the breaking change:

go get -u golang.org/x/exp
go test ./...
# github.com/ProtonMail/go-proton-api
./address.go:21:33: type func(a Address, b Address) bool of func(a, b Address) bool {…} does not match inferred type func(a Address, b Address) int for func(a E, b E) int
?   	github.com/ProtonMail/go-proton-api/server/cmd/client	[no test files]
?   	github.com/ProtonMail/go-proton-api/server/proto	[no test files]
FAIL	github.com/ProtonMail/go-proton-api [build failed]
FAIL	github.com/ProtonMail/go-proton-api/server [build failed]
FAIL	github.com/ProtonMail/go-proton-api/server/backend [build failed]
FAIL

Thank you for exposing and maintaining the proton api client.

[zoop-btc]

would be nice to get this fix in