ENH: Update GitHub Actions to checkout v2

Author: thewtex

.github/workflows/build-test-package.yml

@@ -27,7 +27,7 @@ jobs:
             cmake-build-type: "MinSizeRel"
 
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v2
 
     - name: Set up Python 3.8
       uses: actions/setup-python@v2

{{cookiecutter.project_name}}/.github/workflows/build-test-package.yml

@@ -27,7 +27,7 @@ jobs:
             cmake-build-type: "MinSizeRel"
 
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v2
 
     - name: Set up Python 3.8
       uses: actions/setup-python@v2