fix: dart_frog build generates pubspec_overrides on Windows using backslash causing Failure to deploy on GCloud

[andreykuzovlevv]

Description

basically thats what i got when build

dependency_overrides: {shared: {path: .dart_frog_path_dependencies\shared}}
resolution: null

Changing backslash to forward slash fixed the issue with deployment

Steps To Reproduce

Use windows
add as a dependency a package outside app,

try to deploy that on gcloud

Expected Behavior

build would fail and
pubspec overrides file should now point at .dart_frog_path_dependencies with backslash like so:
dependency_overrides: {shared: {path: .dart_frog_path_dependencies\package_name }}

Additional Context

No response