Update packages even if they're installed on Travis already.

Author: gsnedders

requirements-install.sh

@@ -5,14 +5,14 @@ if [[ $USE_OPTIONAL != "true" && $USE_OPTIONAL != "false" ]]; then
   exit 1
 fi
 
-pip install -r requirements-test.txt
+pip install -U -r requirements-test.txt
 
 if [[ $USE_OPTIONAL == "true" ]]; then
   if [[ $TRAVIS_PYTHON_VERSION == "pypy" || $TRAVIS_PYTHON_VERSION == "pypy3" ]]; then
-    pip install -r requirements-optional.txt
+    pip install -U -r requirements-optional.txt
   elif [[ $TRAVIS_PYTHON_VERSION == "2.6" ]]; then
-    pip install -r requirements-optional-2.6.txt
+    pip install -U -r requirements-optional-2.6.txt
   else
-    pip install -r requirements-optional-cpython.txt
+    pip install -U -r requirements-optional-cpython.txt
   fi
 fi