Fix Debian10 apt public key is not available

If you having public key is not available or miss delete trusted.gpg file under /etc/apt/, here are the solution.

Solution

## Example code
apt-key adv --keyserver hkp://pool.sks-keyservers.net:80 --recv-keys THE_MISSING_KEY_HERE

## Example 
apt-key adv --keyserver hkp://pool.sks-keyservers.net:80 --recv-keys FF389421CBC8B383

## You will received 

apt-key adv --keyserver hkp://pool.sks-keyservers.net:80 --recv-keys FF389421CBC8B383
Executing: /tmp/apt-key-gpghome.StOVFNWWCr/gpg.1.sh --keyserver hkp://pool.sks-keyservers.net:80 --recv-keys FF389421CBC8B383
gpg: key FF389421CBC8B383: public key "PowerDNS Automatic Signing Key " imported
gpg: Total number processed: 1
gpg:               imported: 1