Fix compatibility with Python 3.8-3.9

[JrooTJunior]

Description

Fixed compatibility with Python 3.8-3.9

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an 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

[github-actions]

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[github-actions]

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[codecov]

Codecov Report

Merging #1162 (598c707) into dev-3.x (2c756a1) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##           dev-3.x     #1162   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          354       354           
  Lines         8795      8805   +10     
=========================================
+ Hits          8795      8805   +10     

Flag	Coverage Δ
unittests	100.00% <100.00%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
aiogram/dispatcher/dispatcher.py	100.00% <100.00%> (ø)

... and 1 file with indirect coverage changes