Bump retain_mut from 0.1.3 to 0.1.4 (#10021)

Bumps [retain_mut](https://github.com/upsuper/retain_mut) from 0.1.3 to 0.1.4.
- [Release notes](https://github.com/upsuper/retain_mut/releases)
- [Commits](https://github.com/upsuper/retain_mut/commits)

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

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

substrate/client/consensus/babe/Cargo.toml

@@ -50,7 +50,7 @@ schnorrkel = { version = "0.9.1", features = ["preaudit_deprecated"] }
 rand = "0.7.2"
 merlin = "2.0"
 derive_more = "0.99.2"
-retain_mut = "0.1.3"
+retain_mut = "0.1.4"
 async-trait = "0.1.50"
 
 [dev-dependencies]

substrate/client/transaction-pool/Cargo.toml

@@ -32,7 +32,7 @@ sp-blockchain = { version = "4.0.0-dev", path = "../../primitives/blockchain" }
 sc-utils = { version = "4.0.0-dev", path = "../utils" }
 serde = { version = "1.0.126", features = ["derive"] }
 linked-hash-map = "0.5.4"
-retain_mut = "0.1.3"
+retain_mut = "0.1.4"
 
 [dev-dependencies]
 assert_matches = "1.3.0"