Use debhelper-compat instead of debian/compat

debian/changelog

@@ -1,8 +1,12 @@
 dulwich (0.19.11-3) UNRELEASED; urgency=medium
 
+  [ Jelmer Vernooij ]
   * Depend on at least urllib3 >= 1.24.1, as older versions lack
     HTTPResponse.geturl().
 
+  [ Ondřej Nový ]
+  * Use debhelper-compat instead of debian/compat.
+
  -- Jelmer Vernooij <jelmer@debian.org>  Sun, 10 Mar 2019 23:59:29 +0000
 
 dulwich (0.19.11-2) unstable; urgency=medium

debian/compat

@@ -1 +0,0 @@
-11

debian/control

@@ -4,7 +4,7 @@ Priority: optional
 Maintainer: Debian Python Modules Team <python-modules-team@lists.alioth.debian.org>
 Uploaders: Jelmer Vernooij <jelmer@debian.org>
 Homepage: https://www.dulwich.io/
-Build-Depends: debhelper (>= 11),
+Build-Depends: debhelper-compat (= 11),
                dh-python,
                git (>= 1:1.7.0.4-2) [!alpha !ppc64 !sparc64 !x32 !ia64],
                pypy-dev [alpha amd64 arm64 armel armhf i386 mips powerpc ppc64el s390x],