Fix some issues reported by lintian

Fix some issues reported by lintian

• Set upstream metadata fields: Bug-Database, Bug-Submit, Contact, Repository-Browse. (upstream-metadata-file-is-missing, upstream-metadata-missing-bug-tracking)

• Update standards version to 4.6.1, no changes needed. (out-of-date-standards-version)

• Set field Upstream-Contact in debian/copyright.

• Remove obsolete field Contact from debian/upstream/metadata (already present in machine-readable debian/copyright).

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.

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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/gnome-screenshot/59809b9c-9cae-4fe6-8844-a6c3faa369a5.

Debdiff

These changes affect the binary packages:

[The following lists of changes regard files as different if they have different names, permissions or owners.]

Files in second set of .debs but not in first

-rw-r--r--  root/root   /usr/lib/debug/.build-id/2e/28bffedc94d63569d3efa6b825f93342cfcd04.debug

Files in first set of .debs but not in second

-rw-r--r--  root/root   /usr/lib/debug/.build-id/be/64b83aa80e43e9bc92549e8313c1e7220f7769.debug

Control files of package gnome-screenshot: lines which differ (wdiff format)

• Depends: libc6 (>= 2.7), 2.34), libcairo2 (>= 1.10.0), libgdk-pixbuf-2.0-0 (>= 2.23.0), libglib2.0-0 (>= 2.39.90), libgtk-3-0 (>= 3.21.4), libhandy-1-0 (>= 1.5.90), libx11-6, libxext6, dconf-gsettings-backend | gsettings-backend

Control files of package gnome-screenshot-dbgsym: lines which differ (wdiff format)

• Build-Ids: be64b83aa80e43e9bc92549e8313c1e7220f7769 2e28bffedc94d63569d3efa6b825f93342cfcd04

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