Update askama requirement from 0.12 to 0.13

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](askama-rs/askama@askama_escape/v0.13.0-pre.0...v0.13.0)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

examples/todomvc/Cargo.toml

@@ -9,10 +9,10 @@ version = "0.0.0"
 crate-type = ["cdylib"]
 
 [build-dependencies]
-askama = "0.12"
+askama = "0.13"
 
 [dependencies]
-askama = "0.12"
+askama = "0.13"
 console_error_panic_hook = "0.1.5"
 js-sys = { path = "../../crates/js-sys" }
 wasm-bindgen = { path = "../../" }