Update neo4j's client and flaky dependencies

[as51340]

Description

Derisk potential update of Neo4j's client by adding support only for current major version.
Also, no need to pin exact version for pytest-flake8.

Pull request type

Please delete options that are not relevant.

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring with functional or API changes
• Refactoring without functional or API changes
• Build or packaging related changes
• Documentation content changes
• Other (please describe):

Related issues

Delete section if this PR doesn't resolve any issues.

Closes (link to issue)

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

######################################

Reviewer checklist (the reviewer checks this part)

• Core feature implementation
• Tests
• Code documentation
• Documentation on gqlalchemy/docs

######################################

[antepusic]

Everything looks good with this PR too

[gbotev1]

@as51340, I'm new to GQLAlchemy, and I saw that this PR appears to be the one that officially stopped supporting Neo4j V5. Given that it's almost a year later, I was hoping you (or someone else from this PR: @katarinasupe or @antepusic) could help provide some clarification on:

1. Why only V4 is officially supported? Is that still the case today?
2. I'm curious to learn more about what the potential negative impacts of upgrading to V5 locally would be?

[antejavor]

Hi @gbotev1, thanks for asking the question, it is more of an effort reason than a technical blocker.

We didn't go and test the GQL on v5, so it is currently sitting on v4, it may work on v5 by default, you can take a look into the following PR to see if everything works on version v5, will let you know when I reach some conclusion here.