Merge branch 'master' into events

Author: alrex

README.md

@@ -102,7 +102,7 @@ See the [OpenTelemetry registry](https://opentelemetry.io/registry/?s=python) fo
 
 See [CONTRIBUTING.md](CONTRIBUTING.md)
 
-We meet weekly on Thursday, and the time of the meeting alternates between 9AM PT and 4PM PT. The meeting is subject to change depending on contributors' availability. Check the [OpenTelemetry community calendar](https://calendar.google.com/calendar/embed?src=google.com_b79e3e90j7bbsa2n2p5an5lf60%40group.calendar.google.com) for specific dates.
+We meet weekly on Thursday at 9AM PT. The meeting is subject to change depending on contributors' availability. Check the [OpenTelemetry community calendar](https://calendar.google.com/calendar/embed?src=google.com_b79e3e90j7bbsa2n2p5an5lf60%40group.calendar.google.com) for specific dates.
 
 Meetings take place via [Zoom video conference](https://zoom.us/j/6729396170).
 

dev-requirements.txt

@@ -1,5 +1,5 @@
 pylint==2.4.4
-flake8==3.7.9
+flake8~=3.7
 isort~=4.3
 black>=19.3b0,==19.*
 mypy==0.770