Update type annotations in cursor.py

[RA80533]

What do these changes do?

Are there changes in behavior for the user?

Related issue number

Checklist

• I think the code is well written
• Unit tests for the changes exist
• Documentation reflects the changes
• Add a new news fragment into the CHANGES folder
  • name it <issue_id>.<type> (e.g. 588.bugfix)
  • if you don't have an issue_id change it to the pr id after creating the PR
  • ensure type is one of the following:
    • .feature: Signifying a new feature.
    • .bugfix: Signifying a bug fix.
    • .doc: Signifying a documentation improvement.
    • .removal: Signifying a deprecation or removal of public API.
    • .misc: A ticket has been closed, but it is not of interest to users.
  • Make sure to use full sentences with correct case and punctuation, for example: Fix issue with non-ascii contents in doctest text files.

[jettify]

Changes looks good, but CI seems unhappy:

flake8 aioodbc tests examples setup.py
[158](https://github.com/aio-libs/aioodbc/actions/runs/4887412629/jobs/8790975578?pr=429#step:5:159)
aioodbc/cursor.py:28:21: F821 undefined name 'Connection'
[159](https://github.com/aio-libs/aioodbc/actions/runs/4887412629/jobs/8790975578?pr=429#step:5:160)
aioodbc/cursor.py:60:38: F821 undefined name 'Connection'
[160](https://github.com/aio-libs/aioodbc/actions/runs/4887412629/jobs/8790975578?pr=429#step:5:161)
aioodbc/cursor.py:199:80: E501 line too long (80 > 79 characters)
[161](https://github.com/aio-libs/aioodbc/actions/runs/4887412629/jobs/8790975578?pr=429#step:5:162)
make: *** [Makefile:11: lint] Error 1
[162](https://github.com/aio-libs/aioodbc/actions/runs/4887412629/jobs/8790975578?pr=429#step:5:163)
Error: Process completed with exit code 2.

you can do

make ci

to run full thing locally.