github actions: update recommended Rust to 1.84.0 #3553

Job	Run time
checks (make -f Makefile clippy, 1.84.0, clippy)	2m 18s
checks (PROFILEDIR=debug make -f Makefile build, 1.84.0, cargo)	1m 29s
checks (PROFILEDIR=debug make -f Makefile build-min, 1.84.0, cargo)	1m 31s
checks (PROFILEDIR=debug make -f Makefile build-min-no-systemd, 1.84.0, cargo)	1m 32s
checks_with_udev (RUST_LOG=stratisd=debug make -f Makefile test-loop, 1.84.0, cargo)	39m 24s
checks (PROFILEDIR=debug make -f Makefile build-utils, 1.84.0, cargo)	1m 22s
checks (PROFILEDIR=debug make -f Makefile build-no-ipc, 1.84.0, cargo)	1m 25s
checks (PROFILEDIR=debug make -f Makefile stratisd-tools, 1.84.0, cargo)	1m 31s
checks (make -f Makefile docs-ci, 1.84.0, cargo)	1m 6s
checks (make -f Makefile test, 1.84.0, cargo)	1m 47s
checks (make -f Makefile build, 1.84.0, cargo)	1m 48s
checks (make -f Makefile build-min, 1.84.0, cargo)	1m 50s
checks (make -f Makefile build-no-ipc, 1.84.0, cargo)	1m 39s
	58m 42s

Provide feedback