Use nimcrypto instead of sysrandom

The sysrandom package fails on 32 bit windows.

quic.nimble

@@ -7,8 +7,8 @@ license = "MIT"
 requires "nim >= 1.2.6"
 requires "stew >= 0.1.0 & < 0.2.0"
 requires "chronos >= 3.0.0 & < 4.0.0"
+requires "nimcrypto >= 0.5.4 & < 0.6.0"
 requires "ngtcp2 >= 0.32.0 & < 0.33.0"
-requires "sysrandom >= 1.1.0 & < 2.0.0"
 requires "upraises >= 0.1.0 & < 0.2.0"
 requires "asynctest >= 0.2.1 & < 0.3.0"
 

quic/transport/connectionid.nim

@@ -1,6 +1,6 @@
 import std/strutils
 import std/hashes
-import pkg/sysrandom
+import pkg/nimcrypto
 
 type ConnectionId* = distinct seq[byte]
 
@@ -14,4 +14,6 @@ proc `$`*(id: ConnectionId): string =
   "0x" & cast[string](id).toHex
 
 proc randomConnectionId*(len = DefaultConnectionIdLength): ConnectionId =
-  ConnectionId(@(getRandomBytes(len)))
+  var bytes = newSeq[byte](len)
+  doAssert len == randomBytes(addr bytes[0], len)
+  ConnectionId(bytes)