E: Repository 'http://ppa.launchpad.net/nginx/development... bionic InRelease' changed its 'Label' value from 'NGINX Mainline' to 'NGINX Mainline (1.15.x)'
N: This must be accepted explicitly before updates for this repository can be applied. See apt-secure(8) manpage for details.
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://packages.blackfire.io/debian any InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 696DBE66A72D76DA
已经安装好几遍了，这里就是过不去。