Release 5.3.0

Pre-release
---
- [x] Backport PRs that have been merged to ``main`` to the maintenance branch. Use the "need backport ..." tag if there is one (but don't rely 100% on it)
- [x] Verify that no other open issue needs to be addressed before the release.
- [x] Test against other ETS packages and other ETS-using projects
- [x] Check MANIFEST, requirements, changelog are still up to date.
- [x] Test building the documentation

Major/Minor Release
-------------------
- [x] Create branch `release/` from `main` branch.
- [x] Set release to ``, and set `IS_RELEASED` is true; commit
- [x] Install from source distribution and run tests again
- [x] Open a PR against `main` with this being the last commit so that CI is built on the release commit
- [x] merge the PR when it is approved
- [x] Create a post-release PR branch from `main` branch.
- [x] Bump the minor version number i.e. `` and set `IS_RELEASED` to false; commit.
- [x] Open a PR against `main`
- [x] Merge the PR when it is approved
- [x] From the commit at which `IS_RELEASED` is true and version is ``, create a new maintenance branch `maint/.` and push it to github
- [x] create a PR branch against `maint/`
- [x] Bump the micro version number i.e. `` and set `IS_RELEASED` to false; commit.
- [x] open a PR against `maint/`
- [x] Merge the PR when it is approved
- [x] From the commit at which `IS_RELEASED` is true and version is ``, tag (annotated!) `git tag -a -m "Release " `
- [x] Push the tag `git push origin `
- [x] Make PR targeting `gh-pages` branch: Generate documentation and copy the content to the branch. Verify that the resulting index.html looks good.
- [x] Update GitHub Release pages https://github.com/enthought/pyface/releases
- [x] Create a release on PyPI
- [x] Test the PyPI package

Post-release
-------------
- [ ] Package update for `enthought/free` repository (for EDM)
- [ ] Announcement (e.g. Google Group)