fix(deps): bump jsonwebtoken to 10, git2 to 0.20, gix to 0.81 for security advisories

- seambot: jsonwebtoken 9 -> 10 (>= 10.3.0 required)
- finishingbot: git2 0.19 -> 0.20 (>= 0.20.4 required)
- rhodibot: gix 0.76 -> 0.81 (resolves gix-date < 0.12.0 advisory)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

bots/finishingbot/Cargo.lock

@@ -35,7 +35,7 @@ tracing-subscriber = { version = "0.3", features = ["env-filter", "json"] }
 tracing-appender = "0.2"
 
 # Git operations
-git2 = "0.19"
+git2 = "0.20"
 
 # HTTP client (for license verification)
 reqwest = { version = "0.12", features = ["json", "rustls-tls"], default-features = false }