Merge branch 'rtd-webhook-via-ci' into 'main'

Trigger readthedocs webhook via GitLab CI

Closes #6

See merge request !7

.gitlab-ci.yml

+stages:
+  - deploy
+
+readthedocs:
+  image: alpine:3.15
+  stage: deploy
+  before_script:
+    - apk add curl
+  script:
+    - curl -X POST -d "branches=$CI_DEFAULT_BRANCH" -d "token=$RTD_TOKEN" https://readthedocs.org/api/v2/webhook/tetrax/190009/
+  rules:
+    # Only run the job on the default branch and not in forks.
+    - if: $CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH && $CI_PROJECT_PATH == "micromagnetic-modeling/tetrax"