Fix some issues reported by lintian

Fix some issues reported by lintian

• Trim trailing whitespace. (trailing-whitespace)
• Bump debhelper from old 11 to 13. (package-uses-old-debhelper-compat-version)
• Set debhelper-compat version in Build-Depends. (uses-debhelper-compat-file)
• Set upstream metadata fields: Repository. (upstream-metadata-file-is-missing)

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Build and test logs for this branch can be found at https://janitor.debian.net/lintian-fixes/pkg/sleepenh/d60d4894-f3a5-47a5-927b-91a4404d9a04.

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/14/ffbc0013c2c6b92f037098ece0629b3dd26929.debug

Files in first set of .debs but not in second

-rw-r--r--  root/root   /usr/lib/debug/.build-id/78/ed7925cdf6325f177d422be52317b6541eb083.debug

No differences were encountered between the control files of package **sleepenh**

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

• Build-Ids: 78ed7925cdf6325f177d422be52317b6541eb083 14ffbc0013c2c6b92f037098ece0629b3dd26929

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