Update gpg.sh to upstream version
Update gpg.sh to upstream version

Current as of bitcoin/bitcoin be992701b018f256db6d64786624be4cb60d8975

bitcoin-core/bitcoincore.org,bitcoin-core/bitcoincore.org,bitcoin-core/bitcoincore.org,bitcoin-core/bitcoincore.org,bitcoin-core/bitcoincore.org,bitcoin-core/bitcoincore.org