Fix compilation problems due to ed25519-dalek 1.0.0-pre.4 (#6676)

* Fix compilation problems due to ed25519-dalek 1.0.0-pre.4

* Update libp2p-core

* Revert rand downgrade

substrate/Cargo.lock

@@ -1141,15 +1141,26 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fea41bba32d969b513997752735605054bc0dfa92b4c56bf1189f2e174be7a10"
 
 [[package]]
-name = "ed25519-dalek"
-version = "1.0.0-pre.3"
+name = "ed25519"
+version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "978710b352437433c97b2bff193f2fb1dfd58a093f863dd95e225a19baa599a2"
+checksum = "bf038a7b6fd7ef78ad3348b63f3a17550877b0e28f8d68bcc94894d1412158bc"
+dependencies = [
+ "signature",
+]
+
+[[package]]
+name = "ed25519-dalek"
+version = "1.0.0-pre.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "21a8a37f4e8b35af971e6db5e3897e7a6344caa3f92f6544f88125a1f5f0035a"
 dependencies = [
- "clear_on_drop",
  "curve25519-dalek",
+ "ed25519",
  "rand 0.7.3",
+ "serde",
  "sha2",
+ "zeroize",
 ]
 
 [[package]]
@@ -2759,9 +2770,9 @@ dependencies = [
 
 [[package]]
 name = "libp2p-core"
-version = "0.20.0"
+version = "0.20.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "11ca8d5a64a5d19b45e00e8f24afda6b8e1b605fb25ad7bcf62a42ecf19d7ff3"
+checksum = "6a694fd76d7c33a45a0e6e1525e9b9b5d11127c9c94e560ac0f8abba54ed80af"
 dependencies = [
  "asn1_der",
  "bs58",
@@ -7325,6 +7336,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "signature"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "65211b7b6fc3f14ff9fc7a2011a434e3e6880585bd2e9e9396315ae24cbf7852"
+
 [[package]]
 name = "slab"
 version = "0.4.2"