Bump pytz from 2018.9 to 2020.1

Bumps [pytz](https://github.com/stub42/pytz) from 2018.9 to 2020.1.
- [Release notes](https://github.com/stub42/pytz/releases)
- [Commits](stub42/pytz@release_2018.9...release_2020.1)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Author: dependabot-preview[bot]

requirements.in

@@ -7,7 +7,7 @@ pbr==1.10.0
 protobuf==3.11.3
 pyopenssl==18.0.0
 PyYAML==5.2 # PyYAML 5.3 does not support Python 3.4
-pytz==2018.9
+pytz==2020.1
 requests>=2.20.0
 urllib3>=1.24.3
 deprecated==1.2.6

requirements.txt

@@ -18,7 +18,7 @@ pbr==1.10.0               # via -r requirements.in
 protobuf==3.11.3          # via -r requirements.in
 pycparser==2.18           # via cffi
 pyopenssl==18.0.0         # via -r requirements.in
-pytz==2018.9              # via -r requirements.in
+pytz==2020.1              # via -r requirements.in
 pyyaml==5.2               # via -r requirements.in
 requests==2.21.0          # via -r requirements.in
 six==1.10.0               # via cryptography, protobuf, pyopenssl