Make version a valid semver.

[ntoll]

So circup complain that the version is not valid semver. This minor PR corrects this problem. Thanks!

[ladyada]

@brentru

[brentru]

@ladyada The __version__ in __init__.py does not match the release version, since it's the python-rsa package version.
Should the release version for this library follow the python-rsa version, or should I submit a PR to update this version string to match the CircuitPython_RSA library version?

[tannewt]

@brentru comment out the old __version__ and add the appropriate __version__ and __repo__ to every file for CircuitPython consistency please. It's a CircuitPython library now. :-)