ci: use abatilo/actions-poetry with pinned version

Switch back to abatilo/actions-poetry action per review feedback,
with poetry-version pinned to 1.8.5. Kept before setup-python to
avoid Python 3.9 transitive dependency issue.

Co-Authored-By: rlamb@launchdarkly.com <4955475+kinyoklion@users.noreply.github.com>

Author: devin-ai-integration[bot]

.github/workflows/ci.yml

@@ -22,7 +22,9 @@ jobs:
       - uses: actions/checkout@v4
 
       - name: Install poetry
-        run: pipx install poetry==1.8.5
+        uses: abatilo/actions-poetry@7b6d33e44b4f08d7021a1dee3c044e9c253d6439
+        with:
+          poetry-version: "1.8.5"
 
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v5
@@ -68,7 +70,9 @@ jobs:
       - uses: actions/checkout@v4
 
       - name: Install poetry
-        run: pipx install poetry==1.8.5
+        uses: abatilo/actions-poetry@7b6d33e44b4f08d7021a1dee3c044e9c253d6439
+        with:
+          poetry-version: "1.8.5"
 
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v5