Update NEWS.md for the upcoming v4.0.0 release #825

Job	Run time
t8code_w_shipped_submodules_tests / t8code_cmake_tests	5m 18s
preparation (OFF) / cmake_preparation	1m 20s
preparation (ON) / cmake_preparation	1m 13s
sc_p4est_tests (OFF) / sc_p4est_cmake_tests	3m 55s
sc_p4est_tests (ON) / sc_p4est_cmake_tests	3m 40s
t8code_api_tests (ON, Release) / t8code_cmake_tests	5m 7s
t8code_tests (OFF, Debug) / t8code_cmake_tests	3m 51s
t8code_api_tests (ON, Debug) / t8code_cmake_tests	4m 52s
t8code_tests (OFF, Release) / t8code_cmake_tests	3m 51s
t8code_tests (ON, Debug) / t8code_cmake_tests	5m 24s
t8code_linkage_tests (OFF, Debug) / t8code_cmake_tests	10m 13s
t8code_linkage_tests (OFF, Release) / t8code_cmake_tests	10m 2s
t8code_linkage_tests (ON, Debug) / t8code_cmake_tests	12m 56s
t8code_tests (ON, Release) / t8code_cmake_tests	4m 56s
t8code_linkage_tests (ON, Release) / t8code_cmake_tests	13m 12s
t8code_tarball / build	1m 7s
t8code_tarball / test-tarball	4m 20s
	1h 35m 17s

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