tie protocol versions

The protocol version is indicated in the `openapi.yml` file must also be
up to date at compile time in the Rust source code. For now, a comment
to link the Rust constant to the YAML version has been made.

mithril-aggregator/src/http_server/mod.rs

@@ -3,4 +3,8 @@ mod server;
 
 pub use server::{Server, SERVER_BASE_PATH};
 
-pub const MITHRIL_API_VERSION: &str = "0.1.0";
+/// Mithril API protocol version
+/// this is the same as the one in openapi.yml file.
+/// If you want to update this version to reflect changes in the protocol,
+/// please also update the entry in the openapi.yml
+pub const MITHRIL_API_VERSION: &str = "0.0.1";

openapi.yaml

@@ -1,5 +1,9 @@
 openapi: "3.0.0"
 info:
+  # The protocol version is embedded in the code as constant in the
+  # `mithril-aggregator/src/http_server/mod.rs` file. If you plan to update it
+  # here to reflect changes in the API, please also update the constant in the
+  # Rust file.
   version: 0.0.1
   title: Mithril Aggregator Server
   description: |