chore: bump hashbrown to 0.15 (#333)

Author: conr2d

borsh/Cargo.toml

@@ -36,8 +36,8 @@ borsh-derive = { path = "../borsh-derive", version = "~1.5.4", optional = true }
 
 # hashbrown can be used in no-std context.
 # NOTE: There is no reason to restrict use of older versions, but we don't want to get
-# sudden breaking changes with an open range of versions, so we limit the range by not yet released 0.15.0 version:
-hashbrown = { version = ">=0.11,<0.15.0", optional = true }
+# sudden breaking changes with an open range of versions, so we limit the range by not yet released 0.16.0 version:
+hashbrown = { version = ">=0.11,<0.16.0", optional = true }
 bytes = { version = "1", optional = true }
 bson = { version = "2", optional = true }