Add Python 3.14 support

[andersonhc]

Add Python 3.14 support

Checklist:

• A unit test is covering the code added / modified by this PR

• In case of a new feature, docstrings have been added, with also some documentation in the docs/ folder

• A mention of the change is present in CHANGELOG.md

• This PR is ready to be merged

By submitting this pull request, I confirm that my contribution is made under the terms of the GNU LGPL 3.0 license.

[Lucas-C]

Why adding numpy>=2.3.3 there?
Why is it needed to introduce a constraints.txt file?

Wouldn't adding numpy>=2.3.3 to test/requirements.txt be enough?

Maybe that's worth an explanatory comment 🙂

[andersonhc]

I fought pip for a day and couldn't find another solution... It was installing 2.3.3 and then downgrading back to numpy 2.2.6. I believe the problem is a dependency downstream from camelot-py.
I added the constraints file on python 3.14 builds only and skipped the camelot table extraction test on 3.14.
When camelot publish a Python 3.14 compatible build we should be OK to remove this.

I'll add comments to have it documented.

[andersonhc]

@Lucas-C
The Windows build of cpython 3.14 is now using zlib-ng instead of the standard zlib
python/cpython#91349
python/cpython#131438

This change alters the output of zlib.compress, which means that our PDF file comparisons no longer match byte-for-byte between platforms.
The generated compressed streams differ even though the decompressed content is identical.

To mitigate this problem for now I:

• Changed our github workflow to make sure qpdf is used for the Windows tests so we compare uncompressed data
• There were 3 edge cases remaining because of compressed data embedded on PDF files that qpdf won't decompress - I am skipping on Python 3.14+Windows for now

I believe this deserves more thought and a long term solution, but I'm planning on a new release in the next few weeks and I'd like to have 3.14 wheels published.

[Lucas-C]

The Windows build of cpython 3.14 is now using zlib-ng instead of the standard zlib python/cpython#91349 python/cpython#131438
[...]
This change alters the output of zlib.compress, which means that our PDF file comparisons no longer match byte-for-byte between platforms. > I believe this deserves more thought and a long term solution, but I'm planning on a new release in the next few weeks and I'd like to have 3.14 wheels published.

Alright.

So far we did not bother running tests with qpdf under Windows,
I just wonder if it's worth the hassle, and to introduce minor kludges add this?

Just some humble questioning, I approved the PR and I'm fine if you decide to merge it with those additions 🙂