chore(deps): update askama requirement from 0.14 to 0.15 (#600)

Updates the requirements on [askama](https://github.com/askama-rs/askama) to permit the latest version.
- [Release notes](https://github.com/askama-rs/askama/releases)
- [Commits](https://github.com/askama-rs/askama/compare/v0.14.0...v0.15.0)

---
updated-dependencies:
- dependency-name: askama
  dependency-version: 0.15.0
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by:  jokemanfire <hu.dingyang@zte.com.cn>

examples/servers/Cargo.toml

@@ -39,7 +39,7 @@ reqwest = { version = "0.12", features = ["json"] }
 chrono = "0.4"
 uuid = { version = "1.6", features = ["v4", "serde"] }
 serde_urlencoded = "0.7"
-askama = { version = "0.14" }
+askama = { version = "0.15" }
 tower-http = { version = "0.6", features = ["cors"] }
 hyper = { version = "1" }
 hyper-util = { version = "0", features = ["server"] }