User system zlib to avoid header conflict

Author: stewartboogert

.github/workflows/main.yaml

@@ -42,7 +42,7 @@ jobs:
           mkdir geant4-build
           mkdir geant4-${{ matrix.geant4-version }}
           cd geant4-build 
-          cmake -DCMAKE_INSTALL_PREFIX=../geant4-${{ matrix.geant4-version }} ../geant4 -DGEANT4_INSTALL_DATA=ON -DGEANT4_USE_GDML=ON -DGEANT4_USE_SYSTEM_CLHEP=ON
+          cmake -DCMAKE_INSTALL_PREFIX=../geant4-${{ matrix.geant4-version }} ../geant4 -DGEANT4_INSTALL_DATA=ON -DGEANT4_USE_GDML=ON -DGEANT4_USE_SYSTEM_CLHEP=ON -DGEANT4_USE_SYSTEM_ZLIB=ON
           make -j${{ steps.cpu-cores.outputs.count }} 
           make install
           cd ../