Add citation file

CITATION.cff

+cff-version: "1.1.0"
+message: "If you use Theodolite, please cite it using these metadata."
+authors: 
+  -
+    family-names: Henning
+    given-names: "Sören"
+    orcid: "https://orcid.org/0000-0001-6912-2549"
+  -
+    family-names: Hasselbring
+    given-names: Wilhelm
+    orcid: "https://orcid.org/0000-0001-6625-4335"
+title: Theodolite
+version: "0.3.0"
+repository-code: "https://github.com/cau-se/theodolite"
+license: "Apache-2.0"
+doi: "10.1016/j.bdr.2021.100209"

docs/release-process.md

@@ -13,16 +13,18 @@ the following steps according to the release, you are actually performing.
 
 1. Update `codemeta.json` to match the new version. In particular, make sure that `version` points to the version you are releasing and `dateModified` points to the date you are relasing this version. [CodeMeata generator](https://codemeta.github.io/codemeta-generator/) may help you in updating the file.
 
-2. Create a new branch `v0.3` if it does not already exists. This branch will never
+2. Update `CITATION.cff` to match the new version. At least update the `version` field.
+
+3. Create a new branch `v0.3` if it does not already exists. This branch will never
 again be merged into master.
 
-3. Checkout the `v0.3` branch.
+4. Checkout the `v0.3` branch.
 
-4. Update all references to Theodolite Docker images to tag `v0.3.1`. These are the Kubernetes resource definitions in
+5. Update all references to Theodolite Docker images to tag `v0.3.1`. These are the Kubernetes resource definitions in
 `execution`, the references to *latest* in `run_uc.py`, the Docker Compose files in `docker-test` and the example `theodolite.yaml` job.
 
-5. Commit these changes.
+6. Commit these changes.
 
-6. Tag this commit with `v0.3.1`. The corresponding Docker images will be uploaded.
+7. Tag this commit with `v0.3.1`. The corresponding Docker images will be uploaded.
 
-7. Create *releases* for this tag in both, GitLab and GitHub.
+8. Create *releases* for this tag in both, GitLab and GitHub.