How to fix dput ‘error 58: gpgme_op_verify’

Problem:

You want to upload a package to a PPA using dput <filename>.changes, but you see an error message like this:

Checking signature on .changes
gpg: /home/uli/dev/deb-buildscripts/stm8flash_0.1-git261-deb1-1_amd64.changes: error 58: gpgme_op_verify
gpgme_op_verify: GPGME: No data

Solution:

You need to sign your .changes file before uploading! Do this using

debsign -k 1BBC8BAA <filename>.changes

where 1BBC8BAA is your GPG key ID which you intend to sign with.