Maybe make wasm a feature switch?

[SvenFinn]

I'm working on a project that uses indicatif, and I'm trying to add testcontainers-rs for testing. Both crates can compile to WebAssembly even though my project is not targeting WebAssembly.

Unfortunately, each crate pulls in a different version of the WebAssembly toolchain, and since only one WebAssembly linker can exist in a source tree, this causes a conflict that prevents me from using both crates together.

It would be helpful if testcontainers-rs could make its WebAssembly support optional behind a feature flag, similar to how chrono handles it.

Thanks :)