Bump smallvec from 1.5.1 to 1.6.0

Bumps [smallvec](https://github.com/servo/rust-smallvec) from 1.5.1 to 1.6.0.
- [Release notes](https://github.com/servo/rust-smallvec/releases)
- [Commits](https://github.com/servo/rust-smallvec/compare/v1.5.1...v1.6.0)

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

Cargo.lock

@@ -568,9 +568,9 @@ dependencies = [
 
 [[package]]
 name = "smallvec"
-version = "1.5.1"
+version = "1.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ae524f056d7d770e174287294f562e95044c68e88dec909a00d2094805db9d75"
+checksum = "1a55ca5f3b68e41c979bf8c46a6f1da892ca4db8f94023ce0bd32407573b1ac0"
 
 [[package]]
 name = "spin"

Cargo.toml

@@ -29,7 +29,7 @@ ring = "0.16"
 privdrop = "0.5"
 byteorder = "1.3"
 thiserror = "1.0"
-smallvec = "1.5"
+smallvec = "1.6"
 
 [dev-dependencies]
 tempfile = "3"