[TIDY FIRST] Fix core/dbt/version.py type hinting

[QMalcolm]

Resolves #10612

Problem

There were type errors in core/dbt/version.py

Solution

Fix the type errors

Checklist

• I have read the contributing guide and understand what's expected of me.
• I have run this code in development, and it appears to resolve the stated issue.
• This PR includes tests, or tests are not required or relevant for this PR.
• This PR has no interface changes (e.g., macros, CLI, logs, JSON artifacts, config files, adapter interface, etc.) or this PR has already received feedback and approval from Product or DX.
• This PR includes type annotations for new and modified functions.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.86%. Comparing base (f25a474) to head (552c7c9).
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #10613      +/-   ##
==========================================
- Coverage   88.91%   88.86%   -0.05%     
==========================================
  Files         180      180              
  Lines       22760    22760              
==========================================
- Hits        20237    20226      -11     
- Misses       2523     2534      +11     

Flag	Coverage Δ
integration	86.10% <100.00%> (-0.12%)	⬇️
unit	62.33% <100.00%> (ø)

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Components	Coverage Δ
Unit Tests	62.33% <100.00%> (ø)
Integration Tests	86.10% <100.00%> (-0.12%)	⬇️