Fixup failing CI in rust-server due to xmltree dependency #648

Job	Run time
Build Rust (samples/client/others/rust/)	1m 3s
Build Rust (samples/client/petstore/rust/)	41s
Build Rust (samples/server/petstore/rust-server-deprecated/)	2m 47s
Build Rust (samples/server/petstore/rust-axum/)	1m 38s
Build Rust (samples/server/petstore/rust-server/)	2m 42s
	8m 51s

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