build: Fix permissions of cockpit-bridge.pyz
build: Fix permissions of cockpit-bridge.pyz

zipapp only sets the executable bit for the user. This causes problems
when installing it as root but calling it as user (when copying to e.g.
/usr/local/bin/).

martinpitt/cockpit,cockpit-project/cockpit,cockpit-project/cockpit,martinpitt/cockpit,cockpit-project/cockpit,martinpitt/cockpit,cockpit-project/cockpit,martinpitt/cockpit,cockpit-project/cockpit,martinpitt/cockpit