stop using math/rand.Seed and Read in tests, bump go.mod version to 1.20 (#3936)

internal/wire/transport_parameter_test.go

@@ -4,10 +4,11 @@ import (
 	"bytes"
 	"fmt"
 	"math"
-	"math/rand"
 	"net"
 	"time"
 
+	"golang.org/x/exp/rand"
+
 	"github.com/quic-go/quic-go/internal/protocol"
 	"github.com/quic-go/quic-go/internal/qerr"
 	"github.com/quic-go/quic-go/quicvarint"
@@ -31,7 +32,7 @@ var _ = Describe("Transport Parameters", func() {
 	}
 
 	BeforeEach(func() {
-		rand.Seed(GinkgoRandomSeed())
+		rand.Seed(uint64(GinkgoRandomSeed()))
 	})
 
 	appendInitialSourceConnectionID := func(b []byte) []byte {

internal/wire/version_negotiation_test.go

@@ -2,7 +2,6 @@ package wire
 
 import (
 	"encoding/binary"
-	mrand "math/rand"
 
 	"golang.org/x/exp/rand"
 
@@ -15,7 +14,7 @@ import (
 var _ = Describe("Version Negotiation Packets", func() {
 	randConnID := func(l int) protocol.ArbitraryLenConnectionID {
 		b := make(protocol.ArbitraryLenConnectionID, l)
-		_, err := mrand.Read(b)
+		_, err := rand.Read(b)
 		Expect(err).ToNot(HaveOccurred())
 		return b
 	}