release prep 1.6.0 (#1447)

* Updated CHANGELOG for 1.6.0

* add pr link

* update template

Author: atravitz

.github/PULL_REQUEST_TEMPLATE/release_template.md

@@ -6,7 +6,7 @@ Make the PR:
 * [ ] Create a new release-prep branch corresponding to the version name, e.g. `release-prep-v1.2.0`.  Note: please follow [semantic versioning](https://semver.org/).
 * [ ] Check that all user-relevant updates are included in the `news/` rever `.rst` files. You can backfill any additional items by making a new .rst, e.g. `backfill.rst`
 * [ ] Run [rever](https://regro.github.io/rever-docs/index.html#), e.g. `rever 1.2.0`. This will auto-commit `docs/CHANGELOG.md` and remove the `.rst` files from `news/`. 
-* [ ] Verify that`docs/CHANGELOG.md` looks correct.
+* [ ] Verify that`docs/CHANGELOG.rst` looks correct.
 * [ ] Make the PR and verify that CI/CD passes. 
 * [ ] Merge the PR into `main`.
 * [ ] Make a PR into the [example notebooks repository](https://github.com/OpenFreeEnergy/ExampleNotebooks) to update the version used in `showcase/openfe_showcase.ipynb` and `.binder/environment.yml`

docs/CHANGELOG.rst

@@ -4,6 +4,17 @@ Changelog
 
 .. current developments
 
+v1.6.0
+====================
+
+**Added:**
+
+* Added support for openmm 8.3.0 (benchmarking results at `Issue #1377 <https://github.com/OpenFreeEnergy/openfe/issues/1377>`_.
+* Added support for ``python 3.13`` (we no longer guarantee support for ``python 3.10``).
+* Adds a new internal API for defining alchemical restraints (`PR #1043 <https://github.com/OpenFreeEnergy/openfe/pull/1043>`_).
+
+
+
 v1.5.0
 ====================
 This release includes support for openmm 8.2 and numpy v2. Checkpoint interval default frequency has changed, resulting in much smaller file sizes. There are also a few minor changes as a result of migrating to use **konnektor** as the backend for many network generators.