[GitHub Actions] create virtual env on Mac

.github/workflows/testing_external_plugins.yaml

@@ -45,21 +45,23 @@ jobs:
         path: .venv
         key: ${{ runner.os }}-${{ hashFiles('poetry.lock') }}-${{ matrix.python-version }}-v2-namespace-plugins
 
-    - name: Create Virtual Environment
+    - name: Create and Activate Virtual Environment (Linux)
+      if: startsWith(matrix.os, 'ubuntu')
       run: |
         python -m venv .venv
+        source .venv/bin/activate
 
-    - name: Activate Virtual Environment (Linux)
-      if: startsWith(matrix.os, 'ubuntu')
-      run: source .venv/bin/activate
-
-    - name: Activate Virtual Environment (Mac)
+    - name: Create and Activate Virtual Environment (Mac)
       if: startsWith(matrix.os, 'macOS')
-      run: source .venv/bin/activate
+      run: |
+        python3 -m venv .venv
+        source .venv/bin/activate
 
-    - name:  Activate Virtual Environment (Windows)
+    - name: Create and Activate Virtual Environment (Windows)
       if: startsWith(matrix.os, 'windows')
-      run: .\.venv\Scripts\activate.ps1
+      run: |
+        python -m venv .venv
+        .\.venv\Scripts\activate.ps1
 
     - name: Install dependencies
       run: |