Update axum requirement from 0.6.20 to 0.7.1

Updates the requirements on [axum](https://github.com/tokio-rs/axum) to permit the latest version.
- [Release notes](https://github.com/tokio-rs/axum/releases)
- [Changelog](https://github.com/tokio-rs/axum/blob/main/CHANGELOG.md)
- [Commits](tokio-rs/axum@axum-v0.6.20...axum-v0.7.1)

---
updated-dependencies:
- dependency-name: axum
  dependency-type: direct:production
...

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

Cargo.toml

@@ -14,7 +14,7 @@ edition = "2021"
 anyhow = "1.0.75"
 askama = { version = "0.12.1", features = ["with-axum"] }
 askama_axum = "0.3.0"
-axum = { version = "0.6.20", features = ["macros"] }
+axum = { version = "0.7.1", features = ["macros"] }
 axum-extra = { version = "0.8.0", features = ["protobuf"] }
 chrono = "0.4.31"
 dhat = { version = "0.3.2", optional = true }