snap: Try to fix problem with finding qmake

Author: bjorn

snap/snapcraft.yaml

@@ -55,6 +55,8 @@ parts:
     parse-info:
       - usr/share/metainfo/org.mapeditor.Tiled.appdata.xml
     source: .
+    build-environment:
+      - QT_SELECT: qt6
     build-packages:
       - build-essential
       - dpkg-dev
@@ -65,6 +67,7 @@ parts:
       - qt6-declarative-dev
       - qt6-l10n-tools
       - qt6-svg-dev
+      - qtchooser
       - zlib1g-dev
     # FIXME: Python plugin compiles and loads, but can't find platform libraries
     #  - python-dev