Move dependencies to workspace (#4495)

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Inspired by:

44d65f41ac/Cargo.toml (L65)

I took the liberty of removing that comment since I *think* that I got
all "relevant" ones (showing up more than once, sort of).

crates/ecolor/Cargo.toml

@@ -33,7 +33,7 @@ default = []
 #! ### Optional dependencies
 
 ## [`bytemuck`](https://docs.rs/bytemuck) enables you to cast `ecolor` types to `&[u8]`.
-bytemuck = { version = "1.7.2", optional = true, features = ["derive"] }
+bytemuck = { workspace = true, optional = true, features = ["derive"] }
 
 ## [`cint`](https://docs.rs/cint) enables interoperability with other color libraries.
 cint = { version = "0.3.1", optional = true }
@@ -45,4 +45,4 @@ color-hex = { version = "0.2.0", optional = true }
 document-features = { workspace = true, optional = true }
 
 ## Allow serialization using [`serde`](https://docs.rs/serde).
-serde = { version = "1", optional = true, features = ["derive"] }
+serde = { workspace = true, optional = true }