[PATCH] Update tox.ini for python3.8 and fix pypy3.6

[Floris Bruynooghe]

On Mon 15 Jun 2020 at 07:06 -0300, David Bremner wrote:

> Floris Bruynooghe <flub at devork.be> writes:
>
>>  [testenv]
>>  deps =
>> @@ -14,3 +14,6 @@ commands = pytest --cov={envsitepackagesdir}/notmuch2 {posargs}
>>  
>>  [testenv:pypy35]
>>  basepython = pypy3.5
>> +
>> +[testenv:pypy36]
>> +basepython = pypy3.6
>
> I'm not an expert, but should python 3.7 and python 3.8 have similar
> clauses? Or do they work by default?

They do work by default.  But to be honest these two pypy ones are not
fully standardised and rely on me manually ensuring I have both a
pypy3.5 and pypy3.6 binary on my path.  The default thing that works is
just a "pypy3" which doesn't give you any guarantees over the version
you get (other than not pypy2).