Add NSSupportsAutomaticGraphicsSwitching to the Info.plist

https://developer.apple.com/library/archive/qa/qa1734/_index.html
suggests that this will make it possible for Krita to use the
integrated Intel GPU instead of the discrete AMD GPU. AMD drivers
on macOS are the pits, using Intel should be preferred for Krita

CCBUG:409052

krita/Info.plist.template

@@ -36,6 +36,8 @@
     <true/>
     <key>LSRequiresCarbon</key>
     <true/>
+    <key>NSSupportsAutomaticGraphicsSwitching</key>
+    <true/>
     <key>NSHumanReadableCopyright</key>
     <string>${MACOSX_BUNDLE_COPYRIGHT}</string>
     <key>CFBundleDocumentTypes</key>