Changelog for gn: 0+git -> 0+git

152bfad2 Implement a Result<T> type.
6b0190f7 Fix formatter on main branch
73243639 Fix path to build/gen.py.
d1996a79 Add pre-upload checks into ninja targets
64cfb834 Add --exclude-type command-line argument
925dd782 Add CQ to starlark branch
a01a5a9b Refactor main.star to support multiple branches.
f9cea148 Implement rule implementation execution.
3a817c2e Create a simple session type and create a test for it.
37ab73c2 Fix lifetime of starlark struct keys passed to C++.
4ac29005 Rename .bzl to .scl in accordance with design doc guidance.