Add RubyGems credentials configuration step #762

Job	Run time
ci-data	6s
Push source gem	0s
Compile native gem for aarch64-linux	6m 4s
Compile native gem for aarch64-linux-musl	5m 57s
Compile native gem for x86_64-linux	9m 3s
Compile native gem for arm64-darwin	5m 54s
Compile native gem for x86_64-darwin	6m 0s
Compile native gem for x86_64-linux-musl	5m 45s
Compile native gem for x64-mingw-ucrt	5m 55s
	44m 44s

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