build(deps): bump rand from 0.8.1 to 0.8.4

Bumps [rand](https://github.com/rust-random/rand) from 0.8.1 to 0.8.4.
- [Release notes](https://github.com/rust-random/rand/releases)
- [Changelog](https://github.com/rust-random/rand/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rust-random/rand/compare/0.8.1...0.8.4)

---
updated-dependencies:
- dependency-name: rand
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Cargo.lock

@@ -1155,7 +1155,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cfcf0ed7fe52a17a03854ec54a9f76d6d84508d1c0e66bc1793301c73fc8493c"
 dependencies = [
  "byteorder",
- "rand 0.8.1",
+ "rand 0.8.4",
  "rustc-hex",
  "static_assertions",
 ]
@@ -1519,7 +1519,7 @@ dependencies = [
  "group",
  "num_cpus",
  "pasta_curves",
- "rand 0.8.1",
+ "rand 0.8.4",
 ]
 
 [[package]]
@@ -2347,7 +2347,7 @@ dependencies = [
  "funty",
  "group",
  "lazy_static",
- "rand 0.8.1",
+ "rand 0.8.4",
  "static_assertions",
  "subtle",
 ]
@@ -2643,9 +2643,9 @@ dependencies = [
 
 [[package]]
 name = "rand"
-version = "0.8.1"
+version = "0.8.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c24fcd450d3fa2b592732565aa4f17a27a61c65ece4726353e000939b0edee34"
+checksum = "2e7573632e6454cf6b99d7aac4ccca54be06da05aca2ef7423d22d27d4d4bcd8"
 dependencies = [
  "libc",
  "rand_chacha 0.3.1",
@@ -3753,7 +3753,7 @@ dependencies = [
  "futures 0.3.15",
  "futures-core",
  "pin-project 0.4.27",
- "rand 0.8.1",
+ "rand 0.8.4",
  "tokio 0.3.6",
  "tokio-test",
  "tower",
@@ -4465,7 +4465,7 @@ dependencies = [
  "primitive-types",
  "proptest",
  "proptest-derive",
- "rand 0.8.1",
+ "rand 0.8.4",
  "rand_chacha 0.3.1",
  "rand_core 0.6.3",
  "redjubjub",
@@ -4503,7 +4503,7 @@ dependencies = [
  "lazy_static",
  "metrics",
  "once_cell",
- "rand 0.8.1",
+ "rand 0.8.4",
  "serde",
  "spandoc",
  "thiserror",
@@ -4538,7 +4538,7 @@ dependencies = [
  "pin-project 0.4.27",
  "proptest",
  "proptest-derive",
- "rand 0.8.1",
+ "rand 0.8.4",
  "regex",
  "serde",
  "thiserror",
@@ -4654,7 +4654,7 @@ dependencies = [
  "metrics-exporter-prometheus",
  "once_cell",
  "pin-project 0.4.27",
- "rand 0.8.1",
+ "rand 0.8.4",
  "regex",
  "semver 1.0.3",
  "sentry",