fix docker entrypoint
fix docker entrypoint

fixes #3933

mhils/mitmproxy,vhaupert/mitmproxy,vhaupert/mitmproxy,Kriechi/mitmproxy,Kriechi/mitmproxy,mitmproxy/mitmproxy,mhils/mitmproxy,vhaupert/mitmproxy,mitmproxy/mitmproxy,mhils/mitmproxy,vhaupert/mitmproxy,mitmproxy/mitmproxy,mhils/mitmproxy,Kriechi/mitmproxy,mhils/mitmproxy,mitmproxy/mitmproxy,mitmproxy/mitmproxy,Kriechi/mitmproxy