Added checklist for new release

doc/checklist_new_release.md

@@ -0,0 +1,31 @@
+The following steps should be performed before releasing a new stormpy version.
+
+1. Update `CHANGELOG.md`
+   To get all the commits from an author since the last tag execute:
+   ```console
+   git log last_tag..HEAD --author "author_name"
+   ```
+
+2. Update used tool versions:
+   * Update `storm_min_version` in `setup.py`
+   * Update `install_requires` version of pycarl in `setup.py`
+
+3. Check that stormpy builds without errors and all tests are successful
+   * [Travis](https://travis-ci.org/moves-rwth/stormpy) should run successfully
+
+4. Set new stormpy version:
+   * Set new stormpy version in `lib/stormpy/_version.py`
+
+5. Set new tag in git
+   ```console
+   git tag -a new_version
+   git push origin new_version
+   ```
+   Next we push the tag to GitHub. This step requires the GitHub repo to to be configured as a remote.
+   ```console
+   git remote add github https://github.com/moves-rwth/stormpy.git
+   git push github new_version
+   ```
+   The new tag should now be visible on [GitHub](https://github.com/moves-rwth/stormpy/tags)
+
+6. [Add new release](https://github.com/moves-rwth/stormpy/releases/new) in GitHub