Pipenv Updates (#458)

* fixed the bug for pypy-5.8.0

* update pipenv support
Signed-off-by: Kenneth Reitz <me@kennethreitz.org>

bin/steps/pipenv

@@ -9,7 +9,7 @@ if [[ -f Pipfile ]]; then
         /app/.heroku/python/bin/pip install pipenv --upgrade &> /dev/null
 
         # Install the dependencies.
-        /app/.heroku/python/bin/pipenv install --system 2>&1 | indent
+        /app/.heroku/python/bin/pipenv install --system --skip-lock 2>&1 | indent
 
         # Skip pip install, later.
         export SKIP_PIP_INSTALL=1

bin/steps/pipenv-python-version

@@ -2,7 +2,7 @@
 
 # Detect Python-version with Pipenv.
 
-if [[ -f $BUILD_DIR/Pipfile.lock ]]; then
+if [[ -f $BUILD_DIR/Pipfile ]]; then
 
     if [[ ! -f $BUILD_DIR/runtime.txt ]]; then
         if [[ ! -f $BUILD_DIR/Pipfile.lock ]]; then