Add build dependency on python3-dev

This change adds a build dependency on python3-dev in the Debian control
file. This dependency is necessary for building perf.

Fixes #334

debian/templates/control.in

@@ -21,6 +21,7 @@ Build-Depends: asciidoc,
                libssl-dev,
                lz4,
                python3-minimal,
+               python3-dev,
                quilt,
                rsync,
                xmlto,