Merge pull request #1245: Prepare for RTD shallow cloning

.readthedocs.yml

@@ -5,6 +5,15 @@ build:
   os: ubuntu-22.04
   tools:
     python: "3.7"
+  jobs:
+    post_checkout:
+      # Convert the shallow clone to a complete one so author information can be
+      # generated from the full git history in conf.py.
+      - git fetch --unshallow || true
+      # TODO: remove `|| true` once RTD no longer uses complete cloning for this
+      # repo¹ (scheduled² August 28th, 2023).
+      # ¹ https://github.com/readthedocs/readthedocs.org/issues/5689
+      # ² https://support.nextstrain.org/agent/nextstrain/nextstrain/tickets/details/668036000004369027
 
 python:
   install: