Fix some issues reported by lintian

Fix some issues reported by lintian

• Use secure URI in debian/watch. (debian-watch-uses-insecure-uri)
• debian/rules: Use dh_prep rather than "dh_clean -k". (dh-clean-k-is-deprecated)
• Bump debhelper from old 10 to 12. (package-uses-old-debhelper-compat-version)
• Set upstream metadata fields: Repository, Repository-Browse. (upstream-metadata-file-is-missing, upstream-metadata-missing-repository)
• Update watch file format version to 4. (older-debian-watch-file-standard)

This merge proposal was created automatically by the Janitor bot. For more information, including instructions on how to disable these merge proposals, see https://janitor.debian.net/lintian-fixes.

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

The bot will automatically update the merge proposal to resolve merge conflicts or close the merge proposal when all changes are applied through other means (e.g. cherry-picks). Updates may take several hours to propagate.

Build and test logs for this branch can be found at https://janitor.debian.net/lintian-fixes/pkg/lshw/3f1d07ab-e4c6-4c07-b6c6-ba7b6cadf0bf.