Fix missing HTTPMessage.getHeader()

[runlevel5]

Info

• Play1 (1.7.1-35-g557a968a)
• Python 3.7.16

Steps to reproduce:

./play install cas 3.0
~ Will install cas-3.1
~ This module is compatible with: 1.1.x, 1.2.x
~ Do you want to install this version (y/n)? y
~ Installing module cas-3.1...
~
~ Fetching https://www.playframework.com/modules/cas-3.1.zip
Traceback (most recent call last):
  File "./pp/play", line 168, in <module>
    status = cmdloader.commands[play_command].execute(command=play_command, app=play_app, args=remaining_args, env=play_env, cmdloader=cmdloader)
  File "/Users/tle/Work/clui/pp/framework/pym/play/commands/modulesrepo.py", line 67, in execute
    install(app, args, env)
  File "/Users/tle/Work/clui/pp/framework/pym/play/commands/modulesrepo.py", line 476, in install
    Downloader().retrieve(fetch, archive)
  File "/Users/tle/Work/clui/pp/framework/pym/play/commands/modulesrepo.py", line 103, in retrieve
    self.chunk_read(result, destination, report_hook=self.chunk_report)
  File "/Users/tle/Work/clui/pp/framework/pym/play/commands/modulesrepo.py", line 120, in chunk_read
    total_size = response.info().headers['Content-Length'].strip()
AttributeError: 'HTTPMessage' object has no attribute 'headers'

Context

The response.info() returns HTTPMessage object in Python 3 and no longer have the getHeader() method.

[xael-fry]

Merge in master Thanks @runlevel5