chore: update hashbrown to v0.15 (#7)

Author: duncanpharvey

Cargo.lock

@@ -11,7 +11,7 @@ bench = false
 datadog-protos = { version = "0.1.0", default-features = false, git = "https://github.com/DataDog/saluki/", rev = "c89b58e5784b985819baf11f13f7d35876741222" }
 ddsketch-agent = { version = "0.1.0", default-features = false, git = "https://github.com/DataDog/saluki/", rev = "c89b58e5784b985819baf11f13f7d35876741222" }
 derive_more = { version = "1.0.0", features = ["display", "into"] }
-hashbrown = { version = "0.14.3", default-features = false, features = ["inline-more"] }
+hashbrown = { version = "0.15.0", default-features = false, features = ["inline-more"] }
 protobuf = { version = "3.5.0", default-features = false }
 ustr = { version = "1.0.0", default-features = false }
 fnv = { version = "1.0.7", default-features = false }