chore: downgrade git

[ruben-arts]

Force git to an older version. We found that updating to 2.48.1 broke the CI tests for the pypi git dependencies installation with this error:
Rust tests:

──── TRY 3 STDERR:       pixi::integration_rust add_tests::add_pypi_functionality
Created E:\pixi-tmp\.tmpOqbwG8\pixi.toml
Added python~=3.12.0
Added pipx==1.7.1
Added these as pypi-dependencies.
thread 'add_tests::add_pypi_functionality' panicked at tests\integration_rust\add_tests.rs:269:10:
called `Result::unwrap()` on an `Err` value:   × failed to solve the pypi requirements of 'default' 'osx-64'
  ├─▶ Failed to download and build `boltons @ git+https://github.com/mahmoud/
  │   boltons.git@d463c60`
  ├─▶ Git operation failed
  ╰─▶ process didn't exit successfully: `C:
      \a\pixi\pixi\.pixi\envs\default\Library/bin\git.exe init` (exit code:
      128)
      --- stderr
      error: could not write config file E:/rattler-cache/uv-cache/git-v0/
      db/10639de9122d7228/.git/config: Function not implemented
      fatal: could not set 'core.repositoryformatversion' to '0'

Or the python tests:

 FAILED tests/integration_python/test_edge_cases.py::test_pypi_git_deps - AssertionError: Return code was 1, expected 0, stderr:  WARN Using local manifest E:\pixi\pytest-temp\popen-gw1\test_pypi_git_deps0\pixi.toml rather than E:\pixi\pixi.toml from environment variable `PIXI_PROJECT_MANIFEST`
INFO Creating S3 middleware using {}
Error: failed to solve the pypi requirements of 'default' 'linux-64'
   Diagnostic severity: error
   Caused by: Failed to download and build `fancycompleter @ git+[https://github.com/bretello/fancycompleter`](https://github.com/bretello/fancycompleter%60)
   Caused by: Git operation failed
   Caused by: process didn't exit successfully: `E:\pixi\.pixi\envs\default\Library/bin\git.exe init` (exit code: 128)
--- stderr
error: could not write config file E:/rattler-cache/uv-cache/git-v0/db/9ab0b54ab4b6da98/.git/config: Function not implemented
fatal: could not set 'core.repositoryformatversion' to '0'