Prepare 2.12.1rc1. (#16238)

[ci skip-rust]
[ci skip-build-wheels]

src/python/pants/notes/2.12.x.md

@@ -1,5 +1,25 @@
 # 2.12.x Release Series
 
+## 2.12.1rc1 (Jul 19, 2022)
+
+### Plugin API Changes
+
+* Generically compute dynamic defaults for `Field`s (Cherry-pick of #16206) ([#16220](https://github.com/pantsbuild/pants/pull/16220))
+
+### Bug fixes
+
+* Fix scala plugins args order causing cache issues (Cherry-pick of #16228) ([#16233](https://github.com/pantsbuild/pants/pull/16233))
+
+* Fix explicit dependencies of `parametrize`d targets not working for some target types (Cherry-pick of #16197) ([#16213](https://github.com/pantsbuild/pants/pull/16213))
+
+* Fill address parameters in all cases, rather than only when a consumer is `parametrize`d. (Cherry-pick of #16198) ([#16211](https://github.com/pantsbuild/pants/pull/16211))
+
+* Use filelists to make archive creation tasks more reliable (Cherry-pick of #16183) ([#16185](https://github.com/pantsbuild/pants/pull/16185))
+
+### Documentation
+
+* Document the "fromfile" feature. (cherrypick of #16205) ([#16207](https://github.com/pantsbuild/pants/pull/16207))
+
 ## 2.12.1rc0 (Jul 14, 2022)
 
 ### User API Changes