* Update gpg key for aptly repo
It had a new gpg signing key
```
root@2782fc5db71d:/# apt-get update
Hit http://security.debian.org jessie/updates InRelease
Get:1 http://security.debian.org jessie/updates/main amd64 Packages [548 kB]
Get:2 http://repo.aptly.info squeeze InRelease [4868 B]
Ign http://http.debian.net jessie InRelease
Hit http://http.debian.net jessie-updates InRelease
Err http://repo.aptly.info squeeze InRelease
Hit http://http.debian.net jessie Release.gpg
Hit http://http.debian.net jessie Release
Get:3 http://http.debian.net jessie-updates/main amd64 Packages [23.1 kB]
Get:4 http://http.debian.net jessie/main amd64 Packages [9063 kB]
Fetched 9639 kB in 5s (1667 kB/s)
Reading package lists... Done
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://repo.aptly.info squeeze InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 9E3E53F19C7DE460
W: Failed to fetch http://repo.aptly.info/dists/squeeze/InRelease
W: Some index files failed to download. They have been ignored, or old ones used instead.
root@2782fc5db71d:/# apt-key adv --keyserver keys.gnupg.net --recv-keys 9E3E53F19C7DE460
Executing: gpg --ignore-time-conflict --no-options --no-default-keyring --homedir /tmp/tmp.UPB2nL8Y1z --no-auto-check-trustdb --trust-model always --keyring /etc/apt/trusted.gpg --primary-keyring /etc/apt/trusted.gpg --keyring /etc/apt/trusted.gpg.d/debian-archive-jessie-automatic.gpg --keyring /etc/apt/trusted.gpg.d/debian-archive-jessie-security-automatic.gpg --keyring /etc/apt/trusted.gpg.d/debian-archive-jessie-stable.gpg --keyring /etc/apt/trusted.gpg.d/debian-archive-squeeze-automatic.gpg --keyring /etc/apt/trusted.gpg.d/debian-archive-squeeze-stable.gpg --keyring /etc/apt/trusted.gpg.d/debian-archive-wheezy-automatic.gpg --keyring /etc/apt/trusted.gpg.d/debian-archive-wheezy-stable.gpg --keyserver keys.gnupg.net --recv-keys 9E3E53F19C7DE460
gpg: requesting key 9C7DE460 from hkp server keys.gnupg.net
gpg: key 9C7DE460: public key "Andrey Smirnov <me@smira.ru>" imported
gpg: Total number processed: 1
gpg: imported: 1 (RSA: 1)
root@2782fc5db71d:/# apt-get update
```
* switch to stretch + cleanup
It had a new gpg signing key
```
root@2782fc5db71d:/# apt-get update
Hit http://security.debian.org jessie/updates InRelease
Get:1 http://security.debian.org jessie/updates/main amd64 Packages [548 kB]
Get:2 http://repo.aptly.info squeeze InRelease [4868 B]
Ign http://http.debian.net jessie InRelease
Hit http://http.debian.net jessie-updates InRelease
Err http://repo.aptly.info squeeze InRelease
Hit http://http.debian.net jessie Release.gpg
Hit http://http.debian.net jessie Release
Get:3 http://http.debian.net jessie-updates/main amd64 Packages [23.1 kB]
Get:4 http://http.debian.net jessie/main amd64 Packages [9063 kB]
Fetched 9639 kB in 5s (1667 kB/s)
Reading package lists... Done
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://repo.aptly.info squeeze InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 9E3E53F19C7DE460
W: Failed to fetch http://repo.aptly.info/dists/squeeze/InRelease
W: Some index files failed to download. They have been ignored, or old ones used instead.
root@2782fc5db71d:/# apt-key adv --keyserver keys.gnupg.net --recv-keys 9E3E53F19C7DE460
Executing: gpg --ignore-time-conflict --no-options --no-default-keyring --homedir /tmp/tmp.UPB2nL8Y1z --no-auto-check-trustdb --trust-model always --keyring /etc/apt/trusted.gpg --primary-keyring /etc/apt/trusted.gpg --keyring /etc/apt/trusted.gpg.d/debian-archive-jessie-automatic.gpg --keyring /etc/apt/trusted.gpg.d/debian-archive-jessie-security-automatic.gpg --keyring /etc/apt/trusted.gpg.d/debian-archive-jessie-stable.gpg --keyring /etc/apt/trusted.gpg.d/debian-archive-squeeze-automatic.gpg --keyring /etc/apt/trusted.gpg.d/debian-archive-squeeze-stable.gpg --keyring /etc/apt/trusted.gpg.d/debian-archive-wheezy-automatic.gpg --keyring /etc/apt/trusted.gpg.d/debian-archive-wheezy-stable.gpg --keyserver keys.gnupg.net --recv-keys 9E3E53F19C7DE460
gpg: requesting key 9C7DE460 from hkp server keys.gnupg.net
gpg: key 9C7DE460: public key "Andrey Smirnov <me@smira.ru>" imported
gpg: Total number processed: 1
gpg: imported: 1 (RSA: 1)
root@2782fc5db71d:/# apt-get update
```