requirements: restrict pyqt5 version due to PyInstaller issue (#862)

data/pyinstaller_helper.py

@@ -61,6 +61,7 @@ def run_pyinstaller(cmd_list: list, env: list=None):
         with open("pyinstaller/urh.app/Contents/Info.plist", "rb") as f:
             p = plistlib.load(f)
         p["NSHighResolutionCapable"] = True
+        p["NSRequiresAquaSystemAppearance"] = True
         with open("pyinstaller/urh.app/Contents/Info.plist", "wb") as f:
             plistlib.dump(p, f)
 

data/requirements.txt

@@ -1,6 +1,5 @@
 numpy>=1.9; sys_platform != 'win32'
 numpy>=1.9,!=1.16.0,!=1.19.4; sys_platform == 'win32'
-pyqt5; sys_platform != 'win32'
-pyqt5!=5.14.2; sys_platform == 'win32'
+pyqt5<5.15.4 # https://github.com/pyinstaller/pyinstaller/issues/5631
 psutil
 cython!=0.29.18