Fix some issues reported by lintian

Fix some issues reported by lintian

• Trim trailing whitespace. (trailing-whitespace)
• Bump debhelper from old 12 to 13. (package-uses-old-debhelper-compat-version)
• Set upstream metadata fields: Archive, Bug-Database, Bug-Submit, Contact, Name, Repository-Browse. (upstream-metadata-file-is-missing, upstream-metadata-missing-bug-tracking)

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/07/aa19f7532609915320f10fd5b4935bffbcfa7f.debug

Files in first set of .debs but not in second

-rw-r--r--  root/root   /usr/lib/debug/.build-id/e9/810f54368a4ce42ef2ece97779853b623daf97.debug

No differences were encountered between the control files of package **r-cran-conquer**

Control files of package r-cran-conquer-dbgsym: lines which differ (wdiff format)

• Build-Ids: e9810f54368a4ce42ef2ece97779853b623daf97 07aa19f7532609915320f10fd5b4935bffbcfa7f

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Build and test logs for this branch can be found at https://janitor.debian.net/run/8d78a04b-980a-4aec-87a5-968a5c3cc5fc.