MSYS2-packages: [BUG] Failure to Update

Azure and AppVeyor builds started doing this just a few hours ago.

:: Synchronizing package databases...
downloading mingw32.db...
downloading mingw32.db.sig...
error: mingw32: key "(REDACTED)" is unknown
error: mingw32: signature from "David Macek <(REDACTED)>" is unknown trust
error: failed to update mingw32 (invalid or corrupted database (PGP signature))
:: Import PGP key (REDACTED) "David Macek <(REDACTED)>", created: 2018-01-14? [Y/n] 
downloading mingw64.db...
downloading mingw64.db.sig...
error: mingw64: signature from "David Macek <(REDACTED)>" is unknown trust
error: failed to update mingw64 (invalid or corrupted database (PGP signature))
downloading msys.db...
downloading msys.db.sig...
error: msys: signature from "David Macek <(REDACTED)>" is unknown trust
error: failed to update msys (invalid or corrupted database (PGP signature))
error: failed to synchronize all databases
##[error]Cmd.exe exited with code '1'.
Finishing: Update MSYS2