Create list of package versions

versions.md

@@ -0,0 +1,20 @@
+Package versions
+================
+
+This file contains a list of other files where versions of packages are specified so that they can easily be found when upgrading a dependency version, keeping them all in sync. 
+
+In the future it would be advantageous to implement an automated way of keep versions synchronised across files e.g. https://github.com/pre-commit/pre-commit/issues/945#issuecomment-527603460 or preferably parsing `.pre-commit-config.yaml` and using it to `pip install` requirements (see discussion here: https://github.com/brian-team/brian2/pull/1449#issuecomment-1372476018). Until then, the files are listed below for manual checking and updating. 
+
+* [`README.rst`](https://github.com/brian-team/brian2/blob/master/README.rst)
+* [`setup.py`](https://github.com/brian-team/brian2/blob/master/setup.py)
+* [`rtd-requirements.txt`](https://github.com/brian-team/brian2/blob/master/rtd-requirements.txt)
+* [`pyproject.toml`](https://github.com/brian-team/brian2/blob/master/pyproject.toml)
+* [`.pre-commit-config.yaml`](https://github.com/brian-team/brian2/blob/master/.pre-commit-config.yaml)
+* [`docs_sphinx/conf.py`](https://github.com/brian-team/brian2/blob/master/docs_sphinx/conf.py)
+* [`dev/conda-recipe/meta.yaml`](https://github.com/brian-team/brian2/blob/master/dev/conda-recipe/meta.yaml)
+* [`.github/workflows/publish_to_pypi.yml`](https://github.com/brian-team/brian2/blob/master/.github/workflows/publish_to_pypi.yml)
+* [`.github/workflows/test_latest.yml`](https://github.com/brian-team/brian2/blob/master/.github/workflows/test_latest.yml)
+* [`.github/workflows/testsuite.yml`](https://github.com/brian-team/brian2/blob/master/.github/workflows/testsuite.yml)
+* [`.devcontainer/dev-requirements.txt`](https://github.com/brian-team/brian2/blob/master/.devcontainer/dev-requirements.txt)
+* [`.devcontainer/devcontainer.json`](https://github.com/brian-team/brian2/blob/master/.devcontainer/devcontainer.json)
+* [`.devcontainer/Dockerfile`](https://github.com/brian-team/brian2/blob/master/.devcontainer/Dockerfile)