fix(build): Set version without requiring sed

[rhysparry]

This pull request includes a small but important change to the justfile to enhance the version extraction process.

• justfile: Modified the Version export to use trim_start_match instead of sed for removing the 'v' prefix from the version string.

[rhysparry]

This change is part of the following stack:

• fix(build): Set version without requiring sed #27 ◀
  • feat: Include symbols in NuGet package #28

_{Change managed by git-spice.}