Update go.mod deps and Go version.

[bstoll]

go.mod references 1.15 but the any keyword is used:

gribi/v1/proto/gribi_aft/enums/enums.pb.go

Line 368 in 024356c

var file_v1_proto_gribi_aft_enums_enums_proto_goTypes = []any{

This causes issues when trying to import gribi in other packages.

$ go run .
# github.com/openconfig/gribi/v1/proto/gribi_aft/enums
../go/pkg/mod/github.com/openconfig/gribi@v1.8.0/v1/proto/gribi_aft/enums/enums.pb.go:368:59: predeclared any requires go1.18 or later (-lang was set to go1.15; check go.mod)