Move old scipy tests to separate GitHub Action

.github/workflows/main.yml

@@ -19,9 +19,5 @@ jobs:
         docker run --rm scispacy flake8 scispacy
         docker run --rm scispacy black scispacy --check --line-length 88
         docker run --rm scispacy bash scripts/mypy.sh
-        # Test with newer versions of scipy
         docker run --rm scispacy pytest tests/ --cov scispacy --cov-fail-under=20
-        # Test older version of scipy, since some tests can't run on newer scipy
-        docker run --rm scispacy pip install scipy<1.11 \
-            && pytest tests/ --cov scispacy --cov-fail-under=20
 

.github/workflows/old_scipy.yml

@@ -0,0 +1,18 @@
+name: CI (old scipy)
+
+on:
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v1
+      - name: Build and test with Docker using an older version of scipy
+        run: |
+          docker build --tag scispacy .
+          docker run --rm scispacy pip install scipy<1.11 \
+              && pytest tests/