diff --git a/.gitignore b/.gitignore
index 82f3a88..cbc8020 100644
--- a/.gitignore
+++ b/.gitignore
@@ -20,3 +20,4 @@ cabal.project.local
 cabal.project.local~
 .HTF/
 .ghc.environment.*
+stack.yaml.lock
diff --git a/.travis.yml b/.travis.yml
index 99a6089..262788a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -51,7 +51,7 @@ before_install:
   - CABALHOME=$HOME/.cabal
   - export PATH="$CABALHOME/bin:$PATH"
   - TOP=$(pwd)
-  - if [ "$TRAVIS_OS_NAME" = "osx" ]; then brew update; brew upgrade python@3; curl https://haskell.futurice.com/haskell-on-macos.py | python3 - --make-dirs --install-dir=$HOME/.ghc-install --cabal-alias=head install cabal-install-head ${TRAVIS_COMPILER}; fi
+  - if [ "$TRAVIS_OS_NAME" = "osx" ]; then brew update; curl https://haskell.futurice.com/haskell-on-macos.py | python3 - --make-dirs --install-dir=$HOME/.ghc-install --cabal-alias=head install cabal-install-head ${TRAVIS_COMPILER}; fi
   - if [ "$TRAVIS_OS_NAME" = "osx" ]; then HC=$HOME/.ghc-install/ghc/bin/$TRAVIS_COMPILER; HCPKG=${HC/ghc/ghc-pkg}; CABAL=$HOME/.ghc-install/ghc/bin/cabal; fi
   - HCNUMVER=$(( $(${HC} --numeric-version|sed -E 's/([0-9]+)\.([0-9]+)\.([0-9]+).*/\1 * 10000 + \2 * 100 + \3/') ))
   - echo $HCNUMVER
@@ -100,7 +100,7 @@ install:
   - |
     if $GHCHEAD; then
     echo "allow-newer: $($HCPKG list --simple-output | sed -E 's/([a-zA-Z-]+)-[0-9.]+/*:\1/g')" >> $CABALHOME/config
-    
+
     echo "repository head.hackage"                                                        >> $CABALHOME/config
     echo "   url: http://head.hackage.haskell.org/"                                       >> $CABALHOME/config
     echo "   secure: True"                                                                >> $CABALHOME/config