Fix some issues reported by lintian

Fix some issues reported by lintian

• Use secure URI in debian/watch.
• Update standards version to 4.4.1, no changes needed.
• Bump debhelper from old 9 to 12.
• Fix field name typos in debian/copyright.
• Remove obsolete fields Name, Contact from debian/upstream/metadata.

This merge proposal was created automatically by the Janitor bot (https://janitor.debian.net/lintian-fixes).

You can follow up to this merge proposal as you normally would.

Build and test logs for this branch can be found at https://janitor.debian.net/lintian-fixes/pkg/galera-3/bcecaa7d-9cb0-490f-b334-1a3e497208f1.