Add typing for aiopg.sa package

[hyzyla]

What do these changes do?

Added a type hints for aiopg.sa package

Are there changes in behavior for the user?

-

Related issue number

-

Checklist

• [x] I think the code is well written
• [ ] Unit tests for the changes exist
• [ ] Documentation reflects the changes
• [x] 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.

[codecov[bot]]

Codecov Report

Merging #896 (4b89334) into master (0b5e63c) will increase coverage by 0.72%. The diff coverage is 90.69%.

@@            Coverage Diff             @@
##           master     #896      +/-   ##
==========================================
+ Coverage   91.77%   92.50%   +0.72%     
==========================================
  Files           9       12       +3     
  Lines         863     1600     +737     
  Branches      118      191      +73     
==========================================
+ Hits          792     1480     +688     
- Misses         53       84      +31     
- Partials       18       36      +18     

Impacted Files	Coverage Δ
aiopg/sa/transaction.py	83.13% <86.20%> (-1.68%)	:arrow_down:
aiopg/sa/connection.py	86.51% <88.37%> (-1.53%)	:arrow_down:
aiopg/sa/engine.py	97.52% <92.30%> (-1.62%)	:arrow_down:
aiopg/sa/result.py	89.59% <93.44%> (-0.89%)	:arrow_down:
aiopg/connection.py	95.66% <0.00%> (ø)
aiopg/utils.py	87.61% <0.00%> (ø)
aiopg/__init__.py	100.00% <0.00%> (ø)

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[Pliner]

Hi @hyzyla,

Thanks for the contribution.

I am going to release this as beta and try on one of my work projects, where I had to suppress typing errors.