chore: release 0.12.8, begin 0.12.9.dev0 development (#3410)

* chore: bump version to 0.12.8

* chore: begin 0.12.9.dev0 development

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Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "specify-cli"
-version = "0.12.8"
+version = "0.12.9.dev0"
 description = "Specify CLI, part of GitHub Spec Kit. A tool to bootstrap your projects for Spec-Driven Development (SDD)."
 readme = "README.md"
 requires-python = ">=3.11"