fix: replaces older contributing rst by md version

Signed-off-by: Vincent Biret <vibiret@microsoft.com>

CONTRIBUTING.md

@@ -0,0 +1,53 @@
+# Contributing to the Microsoft Graph Core SDK for Python
+
+The Microsoft Graph SDK for python is available for all manner of contribution. There are a couple of different recommended paths to get contributions into the released version of this SDK.
+
+__NOTE__ A signed a contribution license agreement is required for all contributions, and is checked automatically on new pull requests. Please read and sign [the agreement](https://cla.microsoft.com/) before starting any work for this repository.
+
+## File issues
+
+The best way to get started with a contribution is to start a dialog with the owners of this repository. Sometimes features will be under development or out of scope for this SDK and it's best to check before starting work on contribution.
+
+## Submit pull requests for trivial changes
+
+If you are making a change that does not affect the interface components and does not affect other downstream callers, feel free to make a pull request against the __main__ branch.  The main branch will be updated frequently.
+
+Revisions of this nature will result in a 0.0.X change of the version number.
+
+## Submit pull requests for features
+
+If major functionality is being added, or there will need to be gestation time for a change, it should be submitted against the __feature__ branch.
+
+Revisions of this nature will result in a 0.X.X change of the version number.
+
+## Commit message format
+
+To support our automated release process, pull requests are required to follow the [Conventional Commit](https://www.conventionalcommits.org/en/v1.0.0/)
+format.
+
+Each commit message consists of a **header**, an optional **body** and an optional **footer**. The header is the first line of the commit and
+MUST have a **type** (see below for a list of types) and a **description**. An optional **scope** can be added to the header to give extra context.
+
+```
+<type>[optional scope]: <short description>
+<BLANK LINE>
+<optional body>
+<BLANK LINE>
+<optional footer(s)>
+```
+
+The recommended commit types used are:
+
+ - **feat** for feature updates (increments the _minor_ version)
+ - **fix** for bug fixes (increments the _patch_ version)
+ - **perf** for performance related changes e.g. optimizing an algorithm
+ - **refactor** for code refactoring changes
+ - **test** for test suite updates e.g. adding a test or fixing a test
+ - **style** for changes that don't affect the meaning of code. e.g. formatting changes
+ - **docs** for documentation updates e.g. ReadMe update or code documentation updates
+ - **build** for build system changes (gradle updates, external dependency updates)
+ - **ci** for CI configuration file changes e.g. updating a pipeline
+ - **chore** for miscallaneous non-sdk changesin the repo e.g. removing an unused file
+
+Adding a footer with the prefix **BREAKING CHANGE:** will cause an increment of the _major_ version.
+