chore: unused deps (#804)

The crate `rmp-serde` was listed as a dependency but was not used
anywhere in the codebase.
This PR removes it.

Reference: #390

Additional note:
protobuf was also removed in
[#368](#368),
but it still appears in Cargo.lock due to other transitive dependencies.

---------

Co-authored-by: jordan gonzález <30836115+duncanista@users.noreply.github.com>

Author: yoshi-taka

bottlecap/Cargo.lock

@@ -22,7 +22,6 @@ mime = { version = "0.3", default-features = false }
 multipart = { version = "0.18", default-features = false, features = ["server"] }
 nix = { version = "0.26", default-features = false, features = ["feature", "fs"] }
 ordered_hash_map = { version = "0.4", default-features = false }
-protobuf = { version = "3.5", default-features = false }
 regex = { version = "1.10", default-features = false }
 reqwest = { version = "0.12.11", features = ["json", "http2"], default-features = false }
 serde = { version = "1.0", default-features = false, features = ["derive"] }
@@ -37,7 +36,6 @@ hmac = { version = "0.12", default-features = false }
 sha2 = { version = "0.10", default-features = false }
 hex = { version = "0.4", default-features = false, features = ["std"] }
 base64 = { version = "0.22", default-features = false }
-rmp-serde = { version = "1.3.0", default-features = false }
 rustls = { version = "0.23.18", default-features = false, features = ["aws-lc-rs"] }
 rand = { version = "0.8", default-features = false }
 prost = { version = "0.13", default-features = false }