build: upgrade pymongo to 4.7.2

[uniqueg]

Description

• Upgrade pymongo from 3.10.1 to 4.7.2
• Upgrade MongoDB in petstore app Docker Compose configs from 3.6 to 7.0
• Replace pymongo.cursor.count() with pymongo.collection.count_documents() (see note)
• Fix various type checking issues

Fixes #212

Checklist:

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• N/A I have commented my code, particularly in hard-to-understand areas
• [x] I have updated the documentation (or documentation does not need to be updated)
• [x] My changes generate no new warnings
• N/A I have added tests that prove my fix is effective or that my feature works
• [x] New and existing unit tests pass locally with my changes
• [x] I have not reduced the existing code coverage

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 100.00%. Comparing base (19c127b) to head (5a6883b). Report is 10 commits behind head on dev.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## dev #220 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 20 20 Lines 975 974 -1 ========================================= - Hits 975 974 -1 ``` | [Flag](https://app.codecov.io/gh/elixir-cloud-aai/foca/pull/220/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=elixir-cloud-aai) | Coverage Δ | | |---|---|---| | [test_unit](https://app.codecov.io/gh/elixir-cloud-aai/foca/pull/220/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=elixir-cloud-aai) | `100.00% <100.00%> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=elixir-cloud-aai#carryforward-flags-in-the-pull-request-comment) to find out more.

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.