Theia: updates improving python language server

Update versions and tweak a bit python language server config.

After some investigation, I understood that completions where slow for us because jedi add some [buildout support](https://github.com/davidhalter/jedi/blob/cef769ecd8b3a50cd0784d8660b123f4bf0eaec2/jedi/evaluate/sys_path.py#L132-L137) which walks up directories to find a `buildout.cfg` and inspects the corresponding scripts in `bin` to find python package paths. On web runner I have 98 scripts in `~/bin/`, each of them adding between 30 and 50 entries to `sys.path`.

A quick workaround is to create an empty `buildout.cfg` in the current directory or a parent directory before editing python code.

/reviewed-on !509

software/theia/buildout.hash.cfg

@@ -19,8 +19,8 @@ md5sum = c35e6baca37c690bce39ef43825ec42b
 
 [yarn.lock]
 filename = yarn.lock
-md5sum = eb30f0839ef6ce19b89757cf027e3302
+md5sum = fc2f20d496911241a0d9001c445d6158
 
 [python-language-server-requirements.txt]
 filename = python-language-server-requirements.txt
-md5sum = c21a684783b3e746134c3505ce00b757
+md5sum = 242c8359be6893725ad2ac8e3c864eb0

software/theia/python-language-server-requirements.txt

-autopep8==1.4.2
-flake8==3.6.0
-future==0.16.0
-jedi==0.13.1
+appdirs==1.4.3
+attrs==18.2.0
+black==18.9b0
+Click==7.0
+future==0.17.1
+isort==4.3.4
+jedi==0.13.2
 mccabe==0.6.1
-parso==0.3.1
-pluggy==0.8.0
-pycodestyle==2.4.0
+mypy==0.660
+mypy-extensions==0.4.1
+parso==0.3.2
+pluggy==0.8.1
 pydocstyle==3.0.0
-pyflakes==2.0.0
-python-language-server==0.19.0
+pyflakes==2.1.0
+python-jsonrpc-server==0.1.2
+-e git+https://github.com/palantir/python-language-server@50d03d5931d564e9908292ccfa21dd629ee817ba#egg=python_language_server
 rope==0.11.0
-six==1.11.0
+six==1.12.0
 snowballstemmer==1.2.1
-yapf==0.24.0
+toml==0.10.0
+typed-ast==1.2.0
+typeshed==0.0.1
+yapf==0.25.0