Update base tag for release-6.1 to swift-6.1-DEVELOPMENT-SNAPSHOT-2024-12-15-a#476

swiftwasm-bot merged 2 commits intomainswiftwasm/swiftwasm-build:mainfrom

update-base-tag/release-6.1-swift-6.1-DEVELOPMENT-SNAPSHOT-2024-12-15-aswiftwasm/swiftwasm-build:update-base-tag/release-6.1-swift-6.1-DEVELOPMENT-SNAPSHOT-2024-12-15-aCopy head branch name to clipboard