Update pypi package versions (requirements.txt)

Nothing very significant, except that pytest 3.8.0 now shows
DeprecationWarning and PendingDeprecationWarning by default, so I also
updated pytest.ini to hide those.

More info in the pytest docs:
https://docs.pytest.org/en/latest/warnings.html#deprecationwarning-and-pendingdeprecationwarning

tildes/pytest.ini

@@ -1,3 +1,6 @@
 [pytest]
 testpaths = tests
 addopts = -p no:cacheprovider
+filterwarnings =
+    ignore::DeprecationWarning
+    ignore::PendingDeprecationWarning

tildes/requirements.txt

@@ -4,8 +4,8 @@ amqpy==0.13.1
 appdirs==1.4.3
 argon2-cffi==18.3.0
 astroid==2.0.4
-atomicwrites==1.2.0
-attrs==18.1.0
+atomicwrites==1.2.1
+attrs==18.2.0
 backcall==0.1.0
 beautifulsoup4==4.6.3
 black==18.6b4
@@ -62,14 +62,14 @@ pylint==2.1.1
 pylint-plugin-utils==0.4
 pyotp==2.2.6
 pyramid==1.9.2
-pyramid-debugtoolbar==4.4
+pyramid-debugtoolbar==4.5
 pyramid-ipython==0.2
 pyramid-jinja2==2.7
 pyramid-mako==1.0.2
 pyramid-session-redis==1.4.1
 pyramid-tm==2.2
 pyramid-webassets==0.9
-pytest==3.7.3
+pytest==3.8.0
 pytest-mock==1.10.0
 python-dateutil==2.7.3
 python-editor==1.0.3
@@ -85,12 +85,12 @@ simplejson==3.16.0
 six==1.11.0
 snowballstemmer==1.2.1
 SQLAlchemy==1.2.11
-SQLAlchemy-Utils==0.33.3
-stripe==2.6.0
+SQLAlchemy-Utils==0.33.4
+stripe==2.8.1
 testing.common.database==2.0.3
 testing.redis==1.1.1
 titlecase==0.12.0
-toml==0.9.4
+toml==0.9.6
 traitlets==4.3.2
 transaction==2.2.1
 translationstring==1.3