make sure we fetch whole repo history when testing

.github/workflows/test.yaml

@@ -23,6 +23,11 @@ jobs:
     steps:
     - name: Check out repository
       uses: actions/checkout@v4
+      # needed because we use git describe to get a bumpver compatible GITHASH containing version
+      # alternatively can look at using HEXHASH instead. Note that these are purposefully not
+      # documented in the bumpver project, see issues/PRs for more info.
+      with:
+        fetch-depth: 0
     - name: Set up Python
       uses: actions/setup-python@v5
       with: