Ignore invalid versions.

Needed for `setuptools` 66 and higher when checking a package that has invalid versions on PyPI.
Fixes #52.

For example it fails on parsing `collective.recipe.template` because it has a version `1.4dev-r93307`.
See https://pypi.org/simple/collective-recipe-template/

CHANGES.rst

@@ -4,7 +4,10 @@ Changelog
 1.7.1 (unreleased)
 ------------------
 
-- Nothing changed yet.
+- Ignore invalid versions.
+  Needed for ``setuptools`` 66 and higher when checking a package that has invalid versions on PyPI.
+  Fixes `issue 52 <https://github.com/plone/plone.versioncheck/issues/52>`_.
+  [maurits]
 
 
 1.7.0 (2019-03-08)

src/plone/versioncheck/pypi.py

@@ -74,7 +74,13 @@ def check(name, version, session):  # noqa: C901
     releases = sorted(data["releases"])
     for release in releases:
         # major check (overall)
-        rel_v = parse_version(release)
+        try:
+            rel_v = parse_version(release)
+        except Exception:
+            # likely pkg_resources.extern.packaging.version.InvalidVersion
+            # but really any exception can be ignored.
+            # See https://github.com/plone/plone.versioncheck/issues/52
+            continue
         if rel_v <= version:
             continue
         rel_vtuple = mmbp_tuple(rel_v)