Download lazygit 0.64.1

What's Changed
This fixes a few regressions that were introduced in the last release, and some long-standing bugs that I didn't see any reason to hold back until the next big one.

Fixes 🔧
- Fix transitions of entering and exiting filtering mode (e.g. by path or author) by @stefanhaller in #5897
- Fix race in "Stash staged changes" on git versions before 2.35.0 by @stefanhaller in #5903
- Fix several problems with repos whose git dir lives outside the working tree by @stefanhaller in #5910
- Update the UI after stash operations in a single frame by @stefanhaller in #5905
- Honor the conflict-marker-size gitattribute by @stefanhaller in #5902
- Fix hang on quit when confirmOnQuit is true by @stefanhaller in #5919
- Fix pull requests silently disappearing until lazygit is restarted by @stefanhaller in #5921

Maintenance ⚙️
- Don't let integration tests race a background git repack by @stefanhaller in #5898
- update Nix flake dependencies by @TyceHerrman in #5894
- Simplify the run_integration_tests.sh script by @stefanhaller in #5908
- Bump actions/setup-go from 6 to 7 by @dependabot[bot] in #5843
- Bump github.com/kyokomi/emoji/v2 from 2.2.13 to 2.2.14 by @dependabot[bot] in #5813
- Bump mheap/github-action-required-labels from 5.5.2 to 5.6.0 by @dependabot[bot] in #5769
- Bump github.com/lucasb-eyer/go-colorful from 1.4.0 to 1.4.1 by @dependabot[bot] in #5916
- Bump JamesIves/github-sponsors-readme-action from 1.6.0 to 1.6.1 by @dependabot[bot] in #5917