Bump rust from 1.83.0-slim to 1.84.0-slim in /implementations/rust-boon #857

Job	Run time
list	5s
build (lua-jsonschema)	4s
build (python-jschon)	10s
build (dotnet-jsonschema-net)	4s
build (ts-vscode-json-languageservice)	7s
build (java-openapiprocessor)	6s
build (java-json-schema)	4s
build (js-ajv)	4s
build (java-jsonschemafriend)	7s
build (clojure-json-schema)	6s
build (js-hyperjump)	6s
build (rust-jsonschema)	4s
build (python-fastjsonschema)	3s
build (cpp-valijson)	4s
build (php-opis-json-schema)	9s
build (kotlin-kmp-json-schema-validator)	6s
build (java-json-schema-validator)	8s
build (python-jsonschema)	4s
build (ruby-json_schemer)	6s
build (go-gojsonschema)	4s
build (rust-boon)	6s
build (go-jsonschema)	6s
	2m 3s

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