Update dependencies (#2148)

Core dependencies:
- discord.py: Rapptz/discord.py@00a659c6 -> Rapptz/discord.py@00a659c6
- multidict: 4.4.0 -> 4.4.2

[docs]
- pyparsing: 2.2.0 -> 2.2.1
- sphinx: 1.7.8 -> 1.7.9

[test]
- pytest: 3.7.4 -> 3.8.1

[style]
- toml: 0.9.4 -> 0.9.6

----

I've also replaced usages of `discord.utils.get(guild.roles, id=id)` with the new O(1) `guild.get_role(id)` method.

Signed-off-by: Toby <tobyharradine@gmail.com>

setup.py

@@ -18,7 +18,7 @@ requirements = [
     "fuzzywuzzy==0.17.0",
     "idna-ssl==1.1.0",
     "idna==2.7",
-    "multidict==4.4.0",
+    "multidict==4.4.2",
     "python-levenshtein==0.12.0",
     "pyyaml==3.13",
     "raven==6.9.0",
@@ -107,7 +107,7 @@ if __name__ == "__main__":
                 "more-itertools==4.3.0",
                 "pluggy==0.7.1",
                 "py==1.6.0",
-                "pytest==3.7.4",
+                "pytest==3.8.1",
                 "pytest-asyncio==0.9.0",
                 "six==1.11.0",
             ],
@@ -121,7 +121,7 @@ if __name__ == "__main__":
                 "Jinja2==2.10",
                 "MarkupSafe==1.0",
                 "packaging==17.1",
-                "pyparsing==2.2.0",
+                "pyparsing==2.2.1",
                 "six==1.11.0",
                 "Pygments==2.2.0",
                 "pytz==2018.5",
@@ -129,12 +129,12 @@ if __name__ == "__main__":
                 "urllib3==1.23",
                 "six==1.11.0",
                 "snowballstemmer==1.2.1",
-                "sphinx==1.7.8",
+                "sphinx==1.7.9",
                 "sphinx_rtd_theme==0.4.1",
                 "sphinxcontrib-asyncio==0.2.0",
                 "sphinxcontrib-websupport==1.1.0",
             ],
             "voice": ["red-lavalink==0.1.2"],
-            "style": ["black==18.6b4", "click==6.7", "toml==0.9.4"],
+            "style": ["black==18.6b4", "click==6.7", "toml==0.9.6"],
         },
     )