Fetch whole repo and tags to find correct version

This is because fetching tags only doesn't work. See
actions/checkout#1471

The simplest is to download the whole repo, since it's sufficiently
small. The action will take a bit longer, but that's a small price to
pay.

.github/workflows/test_suite.yml

@@ -17,6 +17,10 @@ jobs:
 
     steps:
     - uses: actions/checkout@v4
+      with:
+        fetch-depth: 0
+        fetch-tags: true
+
     - name: Get LFS files
       run: git lfs pull
     # - name: Fix Conda permissions on macOS