Bump future from 0.15.2 to 0.18.2

Bumps [future](https://github.com/PythonCharmers/python-future) from 0.15.2 to 0.18.2.
- [Release notes](https://github.com/PythonCharmers/python-future/releases)
- [Changelog](https://github.com/PythonCharmers/python-future/blob/master/docs/changelog.rst)
- [Commits](https://github.com/PythonCharmers/python-future/commits)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Author: dependabot-preview[bot]

requirements.in

@@ -1,7 +1,7 @@
 asn1==2.2.0
 cryptography>=2.7.0
 cffi>=1.13.0
-future==0.15.2
+future==0.18.2
 itsdangerous==0.24
 pbr==1.10.0
 protobuf==3.7.0

requirements.txt

@@ -11,7 +11,7 @@ cffi==1.13.0              # via -r requirements.in, cryptography
 chardet==3.0.4            # via requests
 cryptography==2.7         # via -r requirements.in, pyopenssl
 deprecated==1.2.6         # via -r requirements.in
-future==0.15.2            # via -r requirements.in
+future==0.18.2            # via -r requirements.in
 idna==2.7                 # via requests
 itsdangerous==0.24        # via -r requirements.in
 pbr==1.10.0               # via -r requirements.in