push.lua is out of date so doesn't work with love 11.x

push.lua repo is already updated and works with love2d 11.x so file can simply be replaced
Ulydev/push@db9213b#diff-d95e747898ef40d004fd6dd0ec4a9c84)

if you use love 11.x you also need to change colours and audio.newsource lines
pong/main.lua for example needs these lines:
love.graphics.clear(.15, .17, .2, 1) (second line in function love.draw())
love.graphics.setColor(0, 1, 0, 1) ( love.graphics.setColor(0, 1, 0, 1))

sounds = {
    ['paddle_hit'] = love.audio.newSource('sounds/paddle_hit.wav', 'static'),
    ['score'] = love.audio.newSource('sounds/score.wav', 'static'),
    ['wall_hit'] = love.audio.newSource('sounds/wall_hit.wav', 'static')
}

after that it seems to work again.