Github runner macOS pip -> pip3

Author: Ovascos

.github/actions/install-dependencies/action.yml

@@ -24,5 +24,5 @@ runs:
         ## gmp and python are already installed in the latest macOS
         # brew install gmp
         # brew install python
-        pip install sympy
+        pip3 install sympy
         echo "Install Mac dependencies [DONE]"