Bump sha2 from 0.9.6 to 0.9.8 (informalsystems#1345)

Bumps [sha2](https://github.com/RustCrypto/hashes) from 0.9.6 to 0.9.8.
- [Release notes](https://github.com/RustCrypto/hashes/releases)
- [Commits](RustCrypto/hashes@sha2-v0.9.6...sha2-v0.9.8)

---
updated-dependencies:
- dependency-name: sha2
  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>

relayer/Cargo.toml

@@ -48,7 +48,7 @@ hex = "0.4"
 bitcoin = { version = "=0.27", features = ["use-serde"] }
 tiny-bip39 = "0.8.0"
 hdpath = { version = "0.6.0", features = ["with-bitcoin"] }
-sha2 = "0.9.6"
+sha2 = "0.9.8"
 tiny-keccak = { version = "2.0.2", features = ["keccak"], default-features = false }
 ripemd160 = "0.9.1"
 bech32 = "0.8.1"