Fix MaxInt64 overflows on ARM 32-bits

[rayae]

math.MaxInt64 is untyped constant. This causes overflow on a 32-bit system.

Reproduce:

$ GOARCH=arm go build example/config/main.go 
go: downloading golang.org/x/net v0.0.0-20210525063256-abc453219eb5
go: downloading golang.org/x/sys v0.0.0-20220114195835-da31bd327af9
go: downloading golang.org/x/text v0.3.6
# github.com/nacos-group/nacos-sdk-go/v2/clients/config_client
clients\config_client\config_client.go:141:45: math.MaxInt64 (untyped int constant 9223372036854775807) overflows int

Edit:
clients\config_client\config_client.go:141:45

max := int64(math.MaxInt64)

[binbin0325]

math.MaxInt may be better

[rayae]

yes its better

[rayae]

i have tested with math.MaxInt and it works fine