Bump pyinstaller version once again

.appveyor.yml

@@ -53,7 +53,7 @@ install:
   # target Python version and architecture
   - ECHO "Install pip requirements:"
   - "python -m pip install -r requirements.txt"
-  - "python -m pip install PyInstaller==3.3"
+  - "python -m pip install PyInstaller==3.6"
 
 before_build:
     # directory that will contain the built files

scripts/setup-osx.sh

@@ -5,4 +5,4 @@ sudo python3 -m ensurepip --upgrade
 # A manual check that the correct version of Python is running.
 python3 --version
 python3 -m pip install -r requirements.txt
-python3 -m pip install PyInstaller==3.3
+python3 -m pip install PyInstaller==3.6