chore(release): Add .deb auto completion script (#1353)

Co-authored-by: GideonBear <87426140+GideonBear@users.noreply.github.com>

Cargo.toml

@@ -71,6 +71,15 @@ extended-description = "Keeping your system up to date usually involves invoking
 section = "utils"
 priority = "optional"
 default-features = true
+assets = [
+  ["target/release/topgrade", "usr/bin/", "755"],
+  ["README.md", "usr/share/doc/topgrade/README.md", "644"],
+  # The man page is automatically generated by topgrade's build process in CI, so
+  # these files aren't actually committed.
+  ["deployment/deb/topgrade.bash", "usr/share/bash-completion/completions/topgrade", "644"],
+  ["deployment/deb/topgrade.fish", "usr/share/fish/vendor_completions.d/topgrade.fish", "644"],
+  ["deployment/deb/_topgrade", "usr/share/zsh/vendor-completions/", "644"],
+]
 
 [target.'cfg(unix)'.dependencies]
 nix = { version = "~0.29", features = ["hostname", "signal", "user"] }