Update copyright year to 2023 (#537)

* Update copyright year to 2023

* Fix auto format elsewhere

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Angus Hollands <goosey15@gmail.com>

docs/conf.py

@@ -5,7 +5,7 @@
 # -- Project information -----------------------------------------------------
 
 project = "MyST-NB"
-copyright = "2022, Executable Book Project"
+copyright = "2023, Executable Book Project"
 author = "Executable Book Project"
 
 master_doc = "index"