Fix some issues reported by lintian

Fix some issues reported by lintian

• Trim trailing whitespace. (file-contains-trailing-whitespace)
• Use secure URI in Homepage field. (homepage-field-uses-insecure-uri)
• Bump debhelper from old 11 to 12. (package-uses-old-debhelper-compat-version)
• Set debhelper-compat version in Build-Depends. (uses-debhelper-compat-file)
• Set upstream metadata fields: Archive, Name, Repository. (upstream-metadata-file-is-missing, upstream-metadata-missing-repository)

This merge proposal was created automatically by the Janitor bot.

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/kchmviewer/daff03f3-a225-4d0c-8d8c-bcf6e5e36a82.

Debdiff

These changes affect the binary packages:

File lists identical (after any substitutions)

Control files of package kchmviewer: lines which differ (wdiff format)

• Homepage: [-http​://www.kchmviewer.net/-] {+https​://www.kchmviewer.net/+}

No differences were encountered between the control files of package **kchmviewer-dbgsym**

You can also view the diffoscope diff (unfiltered).