Migrate to paramstyle="pyformat", following crate-python 2.2.0

[amotl]

About

A few adjustments were necessary to accommodate the test suite to upstream changes in crate-python 2.2.0. The updates show that the improvement might have an impact to downstream users, so we might want to handle it with more care even in retrospective.

References

• Add named parameter support crate-python#795
• Change named param binding to re-use value for same name crate-python#796
• Version 2.2.0 has a negative impact on SQLAchemy dialect's parameter handling and results crate-python#806

[amotl]

Hi @bgunebakan. Please let me know if you think it makes sense to take over this PR, or otherwise close it without much ado at your disposal if relevant fixes are coming from upstream crate-python, so this patch might no longer be needed. Thanks!

• _NAMED_PARAM_RE regex silently drops pyformat placeholders crate-python#809
• Add support for executemany() crate-python#810

[amotl]

Hi. Thank you for adjusting my patch properly. Maybe announce some of the changes as "breaking"?

[kneth]

It is a good change, but we need to explain it carefully in CHANGES.md as it has a big impact for the users' code.

[amotl]

[The change] has a big impact for the users' code.

Maybe bring in a major version bump at the same time to signal this?

[bgunebakan]

It is a good change, but we need to explain it carefully in CHANGES.md as it has a big impact for the users' code.

Thanks, I extended CHANGES.md file with more info about breaking changes.

[mfussenegger]

Left a suggestion for the changes entry.

Otherwise lgtm - but would be great if this could be squashed into 2 commits: One that drops support for the outdated python versions and another one that bumps crate-python + makes the pyformat changes.