Update gotham_derive requirement from 0.6.0 to 0.7.0

Updates the requirements on [gotham_derive](https://github.com/gotham-rs/gotham) to permit the latest version.
- [Release notes](https://github.com/gotham-rs/gotham/releases)
- [Commits](gotham-rs/gotham@gotham-0.6.0...gotham-0.7.0)

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

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

dom/examples/ssr/Cargo.toml

@@ -9,7 +9,7 @@ description = "proof of concept for server-side rendered HTML with moxie-dom"
 [dependencies]
 augdom = { path = "../../augdom" }
 gotham = "0.6.0"
-gotham_derive = "0.6.0"
+gotham_derive = "0.7.0"
 hyper = "0.14"
 mox = { path = "../../../mox" }
 moxie = { path = "../../../" }