Bump minimal required version of MATLAB to R2018b

.gitlab-ci.yml

doc/manual/source/installation-and-configuration.rst

macOS/build.sh

matlab/+mom/get_data_moments.m

matlab/+mom/run.m

matlab/+occbin/mkdatap_anticipated_2constraints_dyn.m

matlab/+occbin/mkdatap_anticipated_dyn.m

matlab/+occbin/solver.m

matlab/+occbin/write_regimes_to_xls.m

matlab/dynare.m

matlab/dynare_config.m

matlab/dynare_estimation.m

matlab/dynare_identification.m

matlab/dynare_solve.m

matlab/epilogue_shock_decomposition.m

matlab/get_path_to_mex_files.m

matlab/graph_decomp_detail.m

matlab/loadjson_.m

matlab/missing/isfile/isfile.m

matlab/missing/stats/+gamrnd/best_1978.m