chore(deps): bump hmac from 0.12.1 to 0.13.0 in /bots/rhodibot

Bumps [hmac](https://github.com/RustCrypto/MACs) from 0.12.1 to 0.13.0.
- [Commits](RustCrypto/MACs@hmac-v0.12.1...hmac-v0.13.0)

---
updated-dependencies:
- dependency-name: hmac
  dependency-version: 0.13.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

bots/rhodibot/Cargo.lock

@@ -31,7 +31,7 @@ serde_json = "1"
 toml = "0.8"
 
 # Crypto for webhook verification
-hmac = "0.12"
+hmac = "0.13"
 sha2 = "0.10"
 hex = "0.4"