Update .travis.yml

Author: gonzalocasas

.travis.yml

@@ -29,7 +29,7 @@ jobs:
       os: windows           # Windows 10.0.17134 N/A Build 17134
       language: shell       # 'language: python' is an error on Travis CI Windows
       before_install:
-        - mkdir /c/Certs && cd /c/Certs && wget --quiet https://curl.haxx.se/ca/cacert.pem && set SSL_CERT_FILE=/c/Certs/cacert.pem
+        - mkdir /Certs && cd /Certs && wget --quiet https://curl.haxx.se/ca/cacert.pem && set SSL_CERT_FILE=/Certs/cacert.pem
         - choco install python --version=3.8.0
         - pip3 install --user --upgrade pip
         - pip3 install cython --install-option="--no-cython-compile"