Define test dependencies separately

Previously, the test dependencies were installed every time the action was ran, even though they are not used by the action.

.github/workflows/libraries_compile-examples.yml

@@ -27,7 +27,7 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          pip install --requirement "$GITHUB_WORKSPACE/libraries/compile-examples/compilesketches/requirements.txt"
+          pip install --requirement "$GITHUB_WORKSPACE/libraries/compile-examples/compilesketches/tests/requirements.txt"
 
       - name: Lint with flake8
         run: |

compilesketches/requirements.txt

@@ -1,5 +1,3 @@
 GitPython==3.1.2
 PyGithub==1.51
-pytest==5.4.2
-pytest-mock==3.1.0
 PyYAML==5.3.1

compilesketches/tests/requirements.txt

@@ -0,0 +1,3 @@
+--requirement ../requirements.txt
+pytest==5.4.2
+pytest-mock==3.1.0