upgrade grpc to 1.20.1

[guanw]

Signed-off-by: Jude Wang judew@uber.com

Which problem is this PR solving?

• Upgrade grpc-go to be 1.20.1 #1491

Short description of the changes

• Upgrade grpc to 1.20.1

[yurishkuro]

lgtm, assuming tests pass

[guanw]

crossdock seems to be flaky again?

[yurishkuro]

it doesn't get to that point, something failing in constructing python image. I kicked it off again.

[yurishkuro]

It's failing on building cassandra schema image

docker build -t jaegertracing/jaeger-cassandra-schema:latest plugin/storage/cassandra/

    Installed /tmp/pip-install-6wlzdxrv/elasticsearch-curator/.eggs/urllib3-1.25.1-py3.7.egg
    Traceback (most recent call last):
      File "/tmp/pip-install-6wlzdxrv/elasticsearch-curator/setup.py", line 37, in <module>
        from cx_Freeze import setup, Executable
    ModuleNotFoundError: No module named 'cx_Freeze'

[codecov]

Codecov Report

Merging #1492 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master    #1492   +/-   ##
=======================================
  Coverage   99.81%   99.81%           
=======================================
  Files         181      181           
  Lines        8651     8651           
=======================================
  Hits         8635     8635           
  Misses          8        8           
  Partials        8        8

Impacted Files	Coverage Δ
cmd/agent/app/reporter/grpc/builder.go	100% <100%> (ø)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 8d239ae...6affdef. Read the comment docs.