Update build_cmake.yml

check if setup-python@v2 improved 3.8 vs 3.9 issues
diff --git a/.github/workflows/build_cmake.yml b/.github/workflows/build_cmake.yml
index 742a712..f9f2d97 100644
--- a/.github/workflows/build_cmake.yml
+++ b/.github/workflows/build_cmake.yml
@@ -50,7 +50,7 @@
       - name: Run C++ tests
         run: cmake --build build --config Release --target ${{ matrix.config.test_target }}
       - name: Set up Python 3.x
-        uses: actions/setup-python@v1
+        uses: actions/setup-python@v2
         with:
           python-version: '3.x' # grabs latest minor version of python3
       - name: Install Python dependencies