chore: Update signing key and keyring to be consistent #91

Job	Run time
test-packaging	3m 15s
test-contract-tests	2m 44s
test-platforms-and-versions (ubuntu-latest, 8)	2m 26s
test-platforms-and-versions (ubuntu-latest, 11)	2m 27s
test-platforms-and-versions (ubuntu-latest, 17)	2m 33s
test-platforms-and-versions (ubuntu-latest, 19)	2m 33s
	15m 58s

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