Fix nightly_cron worflow (#1382)

Summary:
This line was mistakenly deleted in #1381. It currently leads to a "startup failure". See https://github.com/pytorch/botorch/actions/runs/3014394700

Pull Request resolved: #1382

Test Plan:
nightly cron runs
https://github.com/pytorch/botorch/actions/runs/3017300402

Reviewed By: Balandat

Differential Revision: D39357229

Pulled By: saitcakmak

fbshipit-source-id: f38169613a455c50631d19b8ebbbf024a4ef008f

Author: saitcakmak

.github/workflows/nightly.yml

@@ -128,6 +128,7 @@ jobs:
         pip install .[dev]
         pip install git+https://github.com/facebook/Ax.git
         pip install beautifulsoup4 ipython nbconvert jinja2
+    - name: Unit tests
       run: |
         pytest -ra
     - name: Publish latest website