Bump proformaxml from 1.3.0 to 1.4.0

Bumps [proformaxml](https://github.com/openHPI/proformaxml) from 1.3.0 to 1.4.0.
- [Release notes](https://github.com/openHPI/proformaxml/releases)
- [Commits](https://github.com/openHPI/proformaxml/compare/v1.3.0...v1.4.0)

---
updated-dependencies:
- dependency-name: proformaxml
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Gemfile

@@ -33,7 +33,7 @@ gem 'net-pop', require: false
 gem 'net-smtp', require: false
 gem 'nokogiri'
 gem 'pg'
-gem 'proformaxml', '~> 1.3.0'
+gem 'proformaxml', '~> 1.4.0'
 gem 'prometheus_exporter'
 gem 'puma'
 gem 'pundit'