Export cargo bin PATH directly; GITHUB_PATH did not propagate

.gitea/workflows/sandbox.yml

@@ -43,4 +43,6 @@ jobs:
       - name: Test
         run: |
           set -o pipefail          # without this a failing build looks green
+          # GITHUB_PATH from the previous step did not propagate in runner v5.2.2
+          export PATH="$HOME/.cargo/bin:$PATH"
           cargo test 2>&1 | tail -4