Mark the project as Pre-Alpha

Adjust the print statement to be python3 compatible

Mention that we tested on 0.21.4

Extra check: is the new commit really the one we made (thus fast-forward worked)

Keep the git repositories if the test failed

Add exception thrown when we don't know how to access the configuration returned

Sometime there is no value for the asked configuration key

Adjust the merge logic for pygit2 0.21.4

Adjust pygit2_utils to call get_config to retrieve configuration elements

Add an utility method to retrieve configuration from git

Start a list of pygit2 releases with which pygit2_utils has been tested

Adjust the documentation of GitRepo().diff() to account for NoSuchRefError

Enhance the unit-tests to check with longer git hash where needed

If no commit is found via the repository.get() method, raise an exception in GitRepo().diff()

Fix rest syntax