Bug#916715: toulbar2: missing build dependency on zlib1g-dev

[Adrian Bunk]

Source: toulbar2
Version: 1.0.0+dfsg3-1
Severity: serious
Tags: ftbfs

https://tests.reproducible-builds.org/debian/rb-pkg/unstable/amd64/toulbar2.html

...
CMake Error: The following variables are used in this project, but they are set to NOTFOUND.
Please set them or make sure they are set and tested correctly in the CMake files:
ZLIB_LIBRARY
    linked by target "toulbar2" in directory /build/1st/toulbar2-1.0.0+dfsg3