Update certifi from 2018.8.24 to 2018.10.15 (#4140)

requirements/common.txt

@@ -192,9 +192,9 @@ urllib3==1.23 \
     --hash=sha256:b5725a0bd4ba422ab0e66e89e030c806576753ea3ee08554382c14e685d117b5 \
     --hash=sha256:a68ac5e15e76e7e5dd2b8f94007233e01effe3e50e8daddf69acfd81cb686baf
 
-certifi==2018.8.24 \
-    --hash=sha256:456048c7e371c089d0a77a5212fb37a2c2dce1e24146e3b7e0261736aaeaa22a \
-    --hash=sha256:376690d6f16d32f9d1fe8932551d80b23e9d393a8578c5633a2ed39a64861638
+certifi==2018.10.15 \
+    --hash=sha256:339dc09518b07e2fa7eda5450740925974815557727d6bd35d319c1524a04a4c \
+    --hash=sha256:6d58c986d22b038c8c0df30d639f23a3e6d172a05c3583e766f4c0b785c0986a
 
 # required by requests
 chardet==3.0.4 \