Add support for Python 3.10, drop EOL 3.5

[hugovk]

Fixes https://github.com/mkleehammer/pyodbc/issues/954.

Python 3.10.0 final is due for release in October:

• https://www.python.org/dev/peps/pep-0619/

The final release candidate is now out and the Python release team has issued a call to action for community members:

We strongly encourage maintainers of third-party Python projects to prepare their projects for 3.10 compatibilities during this phase. As always, report any issues to the Python bug tracker.

https://discuss.python.org/t/python-3-10-0rc2-is-now-available/10496?u=hugovk

So let's also test and add support for 3.10.

Drops support for EOL Python 3.5.

[keitherskine]

@hugovk Many thanks for this PR, but could you update setup.py to reflect the addition of Python 3.9 and 3.10?

Also, the build tests are failing for Python 3.5. Rather than fix the unit tests, it seems easiest to add #954 into this PR. If you're OK with that, go ahead and comment out the relevant Python 3.5 tests in appveyor.yml, and ubuntu_build.yml, add Python 3.9 tests to appveyor.yml (3.10 is not available there), and remove the reference to Python 3.5 in setup.py. Then the build tests for both Windows and Ubuntu should pass. Many thanks!

[hugovk]

@hugovk Many thanks for this PR, but could you update setup.py to reflect the addition of Python 3.9 and 3.10?

I already added the 3.9 and 3.10 classifiers to setup.py 👍

Also, the build tests are failing for Python 3.5. Rather than fix the unit tests, it seems easiest to add #954 into this PR. If you're OK with that, go ahead and comment out the relevant Python 3.5 tests in appveyor.yml, and ubuntu_build.yml, add Python 3.9 tests to appveyor.yml (3.10 is not available there), and remove the reference to Python 3.5 in setup.py. Then the build tests for both Windows and Ubuntu should pass. Many thanks!

Good idea, removed 3.5!

I also added python_requires to setup.py, so pip knows which package version to install for end users.

---

Whilst we're at it, how about also dropping 2.7? It's been EOL for nearly two years and is little used. Dropping would further reduce the maintenance burden and allow modern features of Python to be used.

Here's the pip installs for pyodbc from PyPI for August 2021:

category	percent	downloads
3.7	71.38%	8,562,696
3.8	15.27%	1,831,650
3.6	6.20%	743,452
2.7	3.02%	362,048
3.5	2.73%	327,753
3.9	0.91%	109,209
null	0.49%	59,002
3.4	0.00%	576
3.10	0.00%	330
3.3	0.00%	3
2.6	0.00%	1
Total		11,996,720

Source: pip install -U pypistats && pypistats python_minor pyodbc --last-month

[hugovk]

Updated now Python 3.10 final is out.

https://discuss.python.org/t/python-3-10-0-is-now-available/10955

[abitrolly]

This is needed to fix broken builds now.

[keitherskine]

@hugovk AppVeyor have at last added Python 3.10 to their Windows VS2019 build. In which case, it would be great if you could add Python 3.10 to the pyodbc appveyor.yml, if you get a chance. Many thanks!

For ref: https://www.appveyor.com/docs/windows-images-software/#python

[hugovk]

@hugovk AppVeyor have at last added Python 3.10 to their Windows VS2019 build. In which case, it would be great if you could add Python 3.10 to the pyodbc appveyor.yml, if you get a chance. Many thanks!

For ref: appveyor.com/docs/windows-images-software/#python

Done!

[hugovk]

By the way, Python 3.6 is EOL in a couple of weeks :)

https://endoflife.date/python