* go.mod: upgrade prysm and the indrect dependency
prysm from v4.0.2 to v4.0.8, and run go mod tidy
* ci: upgrade go version from 1.19 to 1.20
* go-version: upgrade from v1.19 to v1.20
there is some dependency on go v1.20, such as go-libp2p v0.27.8
and also run go mod tidy
* dependency: upgrade docker version for security
it is not a big issue, since docker is only used for test purpose.
* rand: update the usage of math/rand after golang v1.20
2 APIs of math/rand module were deprecated since golang v1.20.
that is: rand.Seed() and rand.Read(), refer: ettps://pkg.go.dev/math/rand
"rand.Seed(seed int64)" has been replaced by: "r := rand.New(rand.NewSource(seed int64))",
need to initialize it with an instance before use
"rand.Read()" has been replaced by "crypto/rand.Read()"
* readme: need golang v1.20+ to build bsc
