Upgrade dependencies to fix vulnerabilities.

Pipfile

@@ -38,8 +38,8 @@ protorpc = "==0.11.1"
 pycrypto = "==2.6.1"
 pygments = "==2.2.0"
 pytz = "==2018.5"
-pyyaml = "==3.13"
-requests = "==2.19.1"
+pyyaml = "==5.1"
+requests = "==2.20.0"
 semantic-version = "==2.6.0"
 # Transitive Dependency having issues: https://github.com/benjaminp/six/issues/210
 six = "==1.10.0"

requirements.txt

@@ -7,14 +7,14 @@ beautifulsoup4==4.6.3
 boltons==18.0.1
 boto==2.49.0
 certifi==2018.4.16
-cffi==1.11.5; platform_python_implementation != 'PyPy'
+cffi==1.12.2; python_version != '3.3.*'
 chardet==3.0.4
 click==6.7
 colored==1.3.93
-cryptography==2.5
+cryptography==2.6.1
 dulwich==0.19.6
 enum34==1.1.6; python_version < '3'
-futures==3.2.0
+futures==3.2.0; python_version >= '2.6'
 gcs-oauth2-boto-plugin-grow==1.14
 gitdb2==2.0.5; python_version != '3.3.*'
 gitpython==2.1.10
@@ -43,8 +43,8 @@ pynacl==1.3.0; python_version != '3.3.*'
 pyopenssl==19.0.0
 python-utils==2.3.0
 pytz==2018.5
-pyyaml==3.13
-requests==2.19.1
+pyyaml==5.1
+requests==2.20.0
 retry-decorator==1.1.0
 rsa==4.0
 semantic-version==2.6.0
@@ -54,7 +54,7 @@ socksipy-branch==1.1
 texttable-fixed==0.8.3
 translitcodec==0.4.0
 uritemplate==3.0.0
-urllib3==1.23
+urllib3==1.23; python_version != '3.3.*'
 watchdog==0.8.3
 webob==1.8.2
 webreview==0.1.1