Merge pull request #4652 from nid5/4642-fix

4642 fix pipenv lock --pre doesn't include prerelease dependencies

Author: frostming

news/4642.bugfix.rst

@@ -0,0 +1 @@
+Fix bug preventing use of pipenv lock --pre

pipenv/utils.py

@@ -705,6 +705,8 @@ def prepare_pip_args(self, use_pep517=False, build_isolation=True):
             pip_args.append("--no-use-pep517")
         if build_isolation is False:
             pip_args.append("--no-build-isolation")
+        if self.pre:
+            pip_args.append("--pre")
         pip_args.extend(["--cache-dir", environments.PIPENV_CACHE_DIR])
         return pip_args