Bump debhelper from old 12 to 13.

Changes-By: lintian-brush
Fixes: lintian: package-uses-old-debhelper-compat-version
See-also: https://lintian.debian.org/tags/package-uses-old-debhelper-compat-version.html

debian/changelog

@@ -3,6 +3,7 @@ python-gnuplotlib (0.38-2) UNRELEASED; urgency=medium
   * Trim trailing whitespace.
   * Set upstream metadata fields: Bug-Submit.
   * Update standards version to 4.5.0, no changes needed.
+  * Bump debhelper from old 12 to 13.
 
  -- Debian Janitor <janitor@jelmer.uk>  Sat, 27 Feb 2021 04:36:06 -0000
 

debian/control

 Source: python-gnuplotlib
 Section: python
 Priority: optional
-Build-Depends: debhelper-compat (= 12), dh-python,
+Build-Depends: debhelper-compat (= 13), dh-python,
                python3-all, python3-setuptools, python3-numpy,
                python3-numpysane,
                gnuplot-qt | gnuplot-x11 | gnuplot-nox | gnuplot5-qt | gnuplot5-x11 | gnuplot5-nox | gnuplot