Viper no longer works on Go < 1.20

[stevenruidigao]

It seems like Viper will no longer compile on Go 1.18, so should the go.mod be updated? (I believe it is because of slog and https://github.com/sagikazarmark/slog-shim/blob/main/go.mod, which require Go 1.20)

When I try to compile code using Viper in 1.18, I get the following errors:

# golang.org/x/exp/slog
/home/steven/go/pkg/mod/golang.org/x/exp@v0.0.0-20230905200255-921286631fa9/slog/level.go:159:13: undefined: atomic.Int64
/home/steven/go/pkg/mod/golang.org/x/exp@v0.0.0-20230905200255-921286631fa9/slog/attr.go:20:19: undefined: StringValue
/home/steven/go/pkg/mod/golang.org/x/exp@v0.0.0-20230905200255-921286631fa9/slog/attr.go:68:19: undefined: GroupValue
/home/steven/go/pkg/mod/golang.org/x/exp@v0.0.0-20230905200255-921286631fa9/slog/handler.go:446:15: undefined: StringValue
/home/steven/go/pkg/mod/golang.org/x/exp@v0.0.0-20230905200255-921286631fa9/slog/json_handler.go:109:20: v.str undefined (type Value has no field or method str)
/home/steven/go/pkg/mod/golang.org/x/exp@v0.0.0-20230905200255-921286631fa9/slog/record.go:192:9: undefined: GroupValue
/home/steven/go/pkg/mod/golang.org/x/exp@v0.0.0-20230905200255-921286631fa9/slog/text_handler.go:99:20: v.str undefined (type Value has no field or method str)
/home/steven/go/pkg/mod/golang.org/x/exp@v0.0.0-20230905200255-921286631fa9/slog/value.go:87:7: undefined: stringptr
/home/steven/go/pkg/mod/golang.org/x/exp@v0.0.0-20230905200255-921286631fa9/slog/value.go:91:7: undefined: groupptr
/home/steven/go/pkg/mod/golang.org/x/exp@v0.0.0-20230905200255-921286631fa9/slog/value.go:173:10: undefined: StringValue
/home/steven/go/pkg/mod/golang.org/x/exp@v0.0.0-20230905200255-921286631fa9/slog/value.go:173:10: too many errors
note: module requires Go 1.20