Bump smallvec from 1.2.0 to 1.6.1 in /atcoder/rust/abc026

Bumps [smallvec](https://github.com/servo/rust-smallvec) from 1.2.0 to 1.6.1.
- [Release notes](https://github.com/servo/rust-smallvec/releases)
- [Commits](servo/rust-smallvec@v1.2.0...v1.6.1)

---
updated-dependencies:
- dependency-name: smallvec
  dependency-type: direct:production
...

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

Author: dependabot[bot]

atcoder/rust/abc026/Cargo.lock

@@ -67,4 +67,4 @@ proconio = { version = "=0.3.6", features = ["derive"] }
 text_io = "=0.1.8"
 whiteread = "=0.5.0"
 rustc-hash = "=1.1.0"
-smallvec = "=1.2.0"
+smallvec = "=1.6.1"