Add changelog for `0.15.0` #452

Job	Run time
rustfmt_check (macos-latest)	9s
rustfmt_check (windows-latest)	47s
build_dynamic_and_test_windows_pre	7m 13s
rustfmt_check (ubuntu-latest)	9s
build_static_and_test_ubuntu (release/6.0, nightly, no valgrind)	5m 50s
docs_rs_check	39s
rust_clippy_check_ubuntu	5m 28s
build_static_and_test_ubuntu (release/6.0, 1.70.0, no valgrind)	5m 43s
rust_clippy_check_windows	2m 34s
build_static_and_test_ubuntu (release/6.1, nightly, no valgrind)	5m 41s
build_static_and_test_ubuntu (release/6.1, 1.70.0, no valgrind)	5m 50s
build_static_and_test_ubuntu (release/7.0, nightly, valgrind)	44m 2s
build_static_and_test_ubuntu (release/7.0, nightly, no valgrind)	6m 27s
build_static_and_test_ubuntu (release/7.0, 1.70.0, no valgrind)	6m 9s
build_dynamic_and_test_windows (nightly)	1m 37s
build_dynamic_and_test_windows (1.70.0)	2m 15s
	1h 40m 33s

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