Fix some issues reported by lintian

Fix some issues reported by lintian

• Bump debhelper from old 12 to 13. (package-uses-old-debhelper-compat-version)

• Update standards version to 4.5.1, no changes needed. (out-of-date-standards-version)

• Avoid explicitly specifying -Wl,--as-needed linker flag. (debian-rules-uses-as-needed-linker-flag)

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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Build and test logs for this branch can be found at https://janitor.debian.net/lintian-fixes/pkg/flip/a2469aa8-b864-4431-8fd2-930ad61b5397.

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/57/8fd527637b1ea81d13dd58007d1dbe3006af08.debug

Files in first set of .debs but not in second

-rw-r--r--  root/root   /usr/lib/debug/.build-id/7d/6c919c4ced28233089e43c563f0a5597764730.debug

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

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

• Build-Ids: 7d6c919c4ced28233089e43c563f0a5597764730 578fd527637b1ea81d13dd58007d1dbe3006af08

You can also view the diffoscope diff (unfiltered).