Add release guide (#878)

* Add basic release guide

* Add update documentation step

* Make the release guide a checklist instead of a list

---------

Co-authored-by: João Dionísio <57299939+Joao-Dionisio@users.noreply.github.com>

CHANGELOG.md

@@ -4,6 +4,7 @@
 ### Added
 - Created Statistics class
 - Added parser to read .stats file
+- Release checklist in `RELEASE.md`
 - Added Python definitions and wrappers for SCIPstartStrongbranch, SCIPendStrongbranch SCIPgetBranchScoreMultiple, 
   SCIPgetVarStrongbranchInt, SCIPupdateVarPseudocost, SCIPgetVarStrongbranchFrac, SCIPcolGetAge, 
   SCIPgetVarStrongbranchLast, SCIPgetVarStrongbranchNode, SCIPallColsInLP, SCIPcolGetAge

CONTRIBUTING.md

@@ -43,14 +43,7 @@ If you find this contributing guide unclear, please open an issue! :)
 How to craft a release
 ----------------------
 
-1. update `CHANGELOG`
-2. increase version number in `src/pyscipopt/__init__.py` according to semantic versioning
-3. commit changes to the master branch
-3. tag new version `git tag vX.Y.Z`
-4. `git push` && `git push --tags`
-5. [create GitHub release](https://github.com/scipopt/PySCIPOpt/releases) based on that tag
-
-A new PyPI package is automatically created by the GitHub actions when pushing a new tag onto the master and the version has been increased. Also the documentation is autmatically created in the process.
+Moved to [RELEASE.md](RELEASE.md).
 
 Design principles of PySCIPOpt
 ==============================

RELEASE.md

@@ -0,0 +1,19 @@
+# Release Checklist
+The following are the steps to follow to make a new PySCIPOpt release. They should mostly be done in order. 
+- [ ] Check if [scipoptsuite-deploy](https://github.com/scipopt/scipoptsuite-deploy) needs a new release, if a new SCIP version is released for example, or new dependencies (change symmetry dependency, add support for papilo/ parallelization.. etc). And Update release links in `pyproject.toml`
+- [ ] Check if the table in [readme](https://github.com/scipopt/PySCIPOpt#installation) needs to be updated. 
+- [ ] Update version number according to semantic versioning [rules](https://semver.org/) in `_version.py`. 
+- [ ] Update `CHANGELOG.md`; Change the `Unlreased` to the new version number and add an empty unreleased section.
+- [ ] Create a release candidate on test-pypi by running the workflow “Build wheels” in Actions->build wheels, with these parameters `upload:true, test-pypi:true` 
+- [ ] If the pipeline passes, test the released pip package on test-pypi by running and checking that it works
+```bash
+pip install -i https://test.pypi.org/simple/ PySCIPOpt
+```
+- [ ] If it works, release on pypi.org with running the same workflow but with `test-pypi:false`.
+- [ ] Then create a tag wit the new version (from the master branch)
+```bash
+git tag vX.X.X
+git push origin vX.X.X
+```
+- [ ] Then make a github [release](https://github.com/scipopt/PySCIPOpt/releases/new) from this new tag. 
+- [ ] Update documentation by running the `Generate Docs` workflow in Actions->Generate Docs.