Fix wrong release version in AppStream XML

[musicinmybrain]

This fixes validation errors:

$ appstream-util validate-relax --nonet /[...]/io.otsaloma.gaupol.appdata.xml
/[...]/io.otsaloma.gaupol.appdata.xml: FAILED:
• tag-invalid           : <release> version was duplicated
Validation of files failed

(Validation with appstreamcli validate 1.0.2 doesn’t complain about this.)

[otsaloma]

Oops. Merging. Do I also need to release 1.14.1 so that the latest version would have a valid file? (I don't know how these AppData files propagate...)

[musicinmybrain]

Oops. Merging. Do I also need to release 1.14.1 so that the latest version would have a valid file? (I don't know how these AppData files propagate...)

For me as maintainer of the Fedora package, it doesn’t matter much: I already patched in this PR.

I caught this because Fedora packaging guidelines require validation at build time. I don’t know if there are any systems or distros where an appstream-util validation failure might not be seen by a human, but might prevent Gaupol from appearing in an “app store” or “software center.” From that perspective, there might be value in a patch release.