Bump Python to 3.7.7

centos-7/Dockerfile

@@ -259,7 +259,7 @@ RUN version=2.4.3 && \
     rm -rf pybind11-${version}*
 
 # Python 3.7
-RUN version=3.7.6 && \
+RUN version=3.7.7 && \
     yum install -y \
         openssl-devel \
         libffi-devel \

windows-1809/base/Dockerfile

@@ -20,7 +20,7 @@ RUN [Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tl
         curl \
         7zip \
         wixtoolset; \
-    Must-Run choco install -y python --version 3.7.6; \
+    Must-Run choco install -y python --version 3.7.7; \
     $env:PATH = "\"$([Environment]::GetEnvironmentVariable('PATH', [EnvironmentVariableTarget]::User));$([Environment]::GetEnvironmentVariable('PATH', [EnvironmentVariableTarget]::Machine))\""; \
     Must-Run python -m pip --no-cache-dir install --no-warn-script-location wheel; \
     Must-Run choco install -y visualstudio2017buildtools; \