Update indexmap requirement from 1.6.2 to 2.2.6

Updates the requirements on [indexmap](https://github.com/indexmap-rs/indexmap) to permit the latest version.
- [Changelog](https://github.com/indexmap-rs/indexmap/blob/master/RELEASES.md)
- [Commits](indexmap-rs/indexmap@1.6.2...2.2.6)

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

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

Author: dependabot[bot]

parameterized-macro/Cargo.toml

@@ -29,7 +29,7 @@ version = "2.0.52"
 features = ["full"]
 
 [dependencies.indexmap]
-version = "1.6.2"
+version = "2.2.6"
 default-features = false
 
 [dev-dependencies]