Update to rand_core 0.6.2.

See https://rustsec.org/advisories/RUSTSEC-2021-0023

Cargo.lock

@@ -2116,7 +2116,7 @@ checksum = "0ef9e7e66b4468674bfcb0c81af8b7fa0bb154fa9f28eb840da5c447baeb8d7e"
 dependencies = [
  "libc",
  "rand_chacha 0.3.0",
- "rand_core 0.6.1",
+ "rand_core 0.6.2",
  "rand_hc 0.3.0",
 ]
 
@@ -2137,7 +2137,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e12735cf05c9e10bf21534da50a147b924d555dc7a547c42e6bb2d5b6017ae0d"
 dependencies = [
  "ppv-lite86",
- "rand_core 0.6.1",
+ "rand_core 0.6.2",
 ]
 
 [[package]]
@@ -2151,9 +2151,9 @@ dependencies = [
 
 [[package]]
 name = "rand_core"
-version = "0.6.1"
+version = "0.6.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c026d7df8b298d90ccbbc5190bd04d85e159eaf5576caeacf8741da93ccbd2e5"
+checksum = "34cf66eb183df1c5876e2dcf6b13d57340741e8dc255b48e40a26de954d06ae7"
 dependencies = [
  "getrandom 0.2.2",
 ]
@@ -2173,7 +2173,7 @@ version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3190ef7066a446f2e7f42e239d161e905420ccab01eb967c9eb27d21b2322a73"
 dependencies = [
- "rand_core 0.6.1",
+ "rand_core 0.6.2",
 ]
 
 [[package]]