Make all dependencies workspace dependencies (#9333)

## Summary

This PR modifies our `Cargo.toml` files to use workspace dependencies
for _all_ dependencies, rather than the status quo of sporadically
trying to use workspace dependencies for those dependencies that are
used across multiple crates. I find the current situation more confusing
and harder to manage, since we have a mix of workspace and crate-local
dependencies, whereas this setup consistently uses the same approach for
all dependencies.

crates/ruff_python_ast/Cargo.toml

@@ -23,7 +23,7 @@ itertools = { workspace = true }
 rustc-hash = { workspace = true }
 serde = { workspace = true, optional = true }
 smallvec = { workspace = true }
-static_assertions = "1.1.0"
+static_assertions = { workspace = true }
 
 [dev-dependencies]
 insta = { workspace = true }