ci: clarify python release dependency install

Signed-off-by: Nathan Gillett <nathan@intentproof.io>

Author: Nathan Gillett

.github/workflows/release-signing-dry-run.yml

@@ -33,8 +33,11 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --upgrade build
-          if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
-          if [ -f pyproject.toml ]; then pip install -e .; fi
+          if [ -f pyproject.toml ]; then
+            pip install -e .
+          elif [ -f requirements.txt ]; then
+            pip install -r requirements.txt
+          fi
 
       - name: Run tests
         run: python -m unittest discover -s tests -v