refactor(reth/Dockerfile): Reference tag not branch #269

Job	Run time
nethermind (linux/amd64, ubuntu-24.04)	2m 37s
geth (linux/amd64, ubuntu-24.04)	3m 12s
nethermind (linux/arm64, ubuntu-24.04-arm)	3m 20s
reth (linux/amd64, ubuntu-24.04, jemalloc,asm-keccak,optimism)	25m 18s
geth (linux/arm64, ubuntu-24.04-arm)	3m 1s
reth (linux/arm64, ubuntu-24.04-arm, jemalloc,optimism)	28m 33s
	1h 6m 1s

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