fix(base.py): add encoding when open changlelog_file

[tyuchx]

#1110

Description

add encoding when open changlelog_file

Checklist

• Add test cases to all the changes you introduce
• Run ./scripts/format and ./scripts/test locally to ensure this change passes linter check and test
• Test the changes on the local machine manually
• Update the documentation for the changes

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.54%. Comparing base (120d514) to head (b0d6b72).
Report is 327 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1133      +/-   ##
==========================================
+ Coverage   97.33%   97.54%   +0.20%     
==========================================
  Files          42       55      +13     
  Lines        2104     2487     +383     
==========================================
+ Hits         2048     2426     +378     
- Misses         56       61       +5     

Flag	Coverage Δ
unittests	97.54% <100.00%> (+0.20%)	⬆️

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

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[woile]

@Lee-W LGTM

[Lee-W]

I feel like we probably should take care other missing encoding as well 🤔 but I'm good with merging it.🙌