Update certifi to 2019.11.28

requirements.txt

@@ -6,7 +6,7 @@
 #
 asn1crypto==0.24.0        # via cryptography
 bcrypt==3.1.4             # via paramiko
-certifi==2018.4.16        # via requests
+certifi==2019.11.28        # via requests
 cffi==1.11.5              # via bcrypt, cryptography, pynacl
 chardet==3.0.4            # via requests
 click-plugins==1.0.3

requirements_dev.txt

@@ -14,7 +14,7 @@ attrs==18.1.0             # via pytest
 babel==2.6.0              # via sphinx
 backcall==0.1.0           # via ipython
 bumpversion==0.5.3
-certifi==2018.4.16        # via requests
+certifi==2019.11.28        # via requests
 cffi==1.11.5              # via cryptography
 chardet==3.0.4            # via requests
 click==6.7                # via pur

requirements_test_all.txt

@@ -13,7 +13,7 @@ attrs==18.1.0             # via pytest
 babel==2.6.0              # via sphinx
 backcall==0.1.0           # via ipython
 bumpversion==0.5.3
-certifi==2018.4.16        # via requests
+certifi==2019.11.28        # via requests
 cffi==1.11.5              # via cryptography
 chardet==3.0.4            # via requests
 colorama==0.3.9           # via hunter