doc: first shot at a contributing guide

CONTRIBUTING.md

@@ -0,0 +1,57 @@
+# How to contribute to protox
+First, thank you for your interest in contributing to protox!
+
+Here are some guidelines to follow and some tips when contributing to protox.
+
+## Development Prerequisites
+- Erlang/OTP 26 or later
+- Elixir 1.15 or later
+- (optional) [lefthook](https://evilmartians.github.io/lefthook/installation) for git hooks
+
+## Development Guidelines
+To enforce consistent code style and quality, we use the following tools:
+- [`mix deps.unlock --check-unused`](https://hexdocs.pm/mix/Mix.Tasks.Deps.Unlock.html) to check for unused dependencies
+- [`mix format --check-formatted`](https://hexdocs.pm/mix/Mix.Tasks.Format.html) to check for code formatting issues
+- [`mix credo`](https://hexdocs.pm/credo/Mix.Tasks.Credo.html) for code style and consistency checks
+- [`mix dialyzer`](https://hexdocs.pm/dialyxir/Mix.Tasks.Dialyzer.html) for type checking
+- [`mix muzak`](https://hexdocs.pm/muzak_pro/muzak-pro.html) for mutation testing
+- `mix test --include conformance` for testing
+
+> [!NOTE]
+>
+> These tasks are always run in the CI pipeline.
+
+> [!NOTE]
+>
+> `lefthook` can be used to run these tasks automatically on each commit or push (except for the `muzak` task which takes a long time to run).
+
+> [!NOTE]
+>
+> `mix test --include conformance` automatically downloads and compilesthe conformance test suite and runs it against the current version of protox.
+
+### Testing
+- Add tests for any new features or bug fixes.
+- Ensure all tests pass with `mix test --include conformance`.
+- Try to maintain or improve test coverage (check with `mix test --cover`).
+
+### Documentation
+- Document public functions using ExDoc format.
+- Update module documentation when needed.
+- If possible, include examples in documentation.
+- Update README.md if needed.
+
+## Pull Request Process
+Submit a Pull Request with:
+- Clear description of changes
+- Reference to any related issues
+- Examples of new functionality if applicable
+
+## License
+By contributing to Protox, you agree that your contributions will be licensed under MIT License.
+
+## Getting Help
+If you have questions or need help, you can:
+- Send me a direct message on [Elixir Forum](https://elixirforum.com/u/ahamez).
+- Send me an email at alexandre.hamez at gmail.com.
+- Open an issue.
+- Start a discussion at https://github.com/ahamez/protox/discussions.

README.md

@@ -51,12 +51,12 @@ You can find [here](https://github.com/ahamez/protox/blob/master/test/example_te
 - [Conformance](#conformance)
 - [Types mapping](#types-mapping)
 - [Benchmarks](#benchmarks)
-- [Development](#development)
+- [Contributing](#contributing)
 - [Credits](#credits)
 
 ## Prerequisites
 
-- Elixir >= 1.12
+- Elixir >= 1.15
 - protoc >= 3.0 *This dependency is only required at compile-time*
   `protox` uses Google's `protoc` (>= 3.0) to parse `.proto` files. It must be available in `$PATH`.
 
@@ -540,7 +540,7 @@ mix protox.conformance
 
 ### Skipped conformance tests
 
-You may have noticed that there are `21 expected failures`. Indeed, we removed on purpose some conformance tests that `protox` can't currently pass. Here are the reasons why:
+You may have noticed that there are `XXX expected failures`. Indeed, we removed on purpose some conformance tests that `protox` can't currently pass. Here are the reasons why:
 
 - [Any](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#any) is not yet supported by `protox`;
 - We could not find the specification for the protobuf2 case of field name extensions when decoding from JSON.
@@ -583,12 +583,9 @@ mix run ./benchmarks/run.exs --lib=./benchmarks/protox.exs
 mix run ./benchmarks/load.exs
 ```
 
-## Development
+## Contributing
 
-`protox` uses [`pre-commit`](https://pre-commit.com/#install) to launch git hooks. Thus, it's strongly recommended to install it, and then to install hooks as follows:
-```sh
-pre-commit install && pre-commit install -t pre-push
-```
+Please see [CONTRIBUTING.md](CONTRIBUTING.md) for more information.
 
 ## Credits