[BUG] Cargo fails to compile. Using h2 0.2.7 causing compilation errors

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

When running cargo build I end up with:

   Compiling h2 v0.2.7
error[E0107]: this struct takes 3 generic arguments but 2 generic arguments were supplied
  --> /home/omar/.cargo/registry/src/github.com-1ecc6299db9ec823/h2-0.2.7/src/proto/streams/store.rs:15:10
   |
15 |     ids: IndexMap<StreamId, SlabIndex>,
   |          ^^^^^^^^ --------  --------- supplied 2 generic arguments
   |          |
   |          expected 3 generic arguments
   |
note: struct defined here, with 3 generic parameters: `K`, `V`, `S`
  --> /home/omar/.cargo/registry/src/github.com-1ecc6299db9ec823/indexmap-1.8.1/src/map.rs:76:12
   |
76 | pub struct IndexMap<K, V, S> {
   |            ^^^^^^^^ -  -  -
help: add missing generic argument
   |
15 |     ids: IndexMap<StreamId, SlabIndex, S>,
   |                                      +++

For more information about this error, try `rustc --explain E0107`.
error: could not compile `h2` due to previous error
warning: build failed, waiting for other jobs to finish...
error: build failed

openapi-generator version

openapi-generator-cli 5.4.0
  commit : unknown
  built  : -999999999-01-01T00:00:00+18:00
  source : https://github.com/openapitools/openapi-generator
  docs   : https://openapi-generator.tech/

Generation Details

Generation command: openapi-generator generate -g rust-server -i api.yml -o api_gen

Steps to reproduce

1. Generate the code using previous command
2. cd into api_gen
3. Run cargo b

Suggest a fix

Change the package versions.

Generate the rust-server project with the shown command, then run cargo build and inspect the generated dependency declarations alongside the h2 v0.2.7 and indexmap v1.8.1 errors. Done means the generated project compiles successfully with compatible package versions.