Don't crash autoupdate on non-PEP440-compliant tool versions

Fix errors like:

```
File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/planemo/commands/cmd_autoupdate.py", line 120, in cli
    tools_to_update = autoupdate.get_tools_to_update(ctx, workflow, tools_to_skip)
                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/planemo/autoupdate.py", line 363, in get_tools_to_update
    return outdated_tools(ctx, wf_dict, ts, tools_to_skip)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/planemo/autoupdate.py", line 349, in outdated_tools
    outdated_tools_rec(wf_dict)
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/planemo/autoupdate.py", line 337, in outdated_tools_rec
    outdated_tool_dict.update(check_tool_step(tool_id))
                              ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/planemo/autoupdate.py", line 324, in check_tool_step
    updated_tool_id = get_newest_tool_id(matching_tool_ids)
                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/planemo/autoupdate.py", line 290, in get_newest_tool_id
    return sorted(
           ^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/planemo/autoupdate.py", line 292, in <lambda>
    key=lambda n: packaging.version.parse(n.split("/")[-1]),
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/packaging/version.py", line 54, in parse
    return Version(version)
           ^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.7/x64/lib/python3.11/site-packages/packaging/version.py", line 200, in __init__
    raise InvalidVersion(f"Invalid version: '{version}'")
packaging.version.InvalidVersion: Invalid version: '0.8.1+galaxy0+galaxy0'
```

by replacing an invalid version with version "0".

planemo/autoupdate.py

@@ -28,6 +28,7 @@
 from planemo.io import (
     error,
     info,
+    warn,
 )
 from planemo.workflow_lint import (
     find_repos_from_tool_id,
@@ -78,6 +79,18 @@ def get_tokens(xml_tree: ElementTree) -> Dict[str, Dict[str, Optional[str]]]:
     return tokens
 
 
+def parse_version(version: str) -> packaging.version.Version:
+    """
+    Parse a version string into a Version object.
+    If the version string is not PEP 440 compliant, return Version("0").
+    """
+    try:
+        return packaging.version.parse(version)
+    except packaging.version.InvalidVersion as e:
+        warn(e)
+        return packaging.version.Version("0")
+
+
 def check_conda(package_name: str, ctx: "PlanemoCliContext", **kwds) -> str:
     """
     Get the most up-to-date conda version for a package.
@@ -89,7 +102,7 @@ def check_conda(package_name: str, ctx: "PlanemoCliContext", **kwds) -> str:
         search_results = itertools.chain.from_iterable(
             n["versions"] for n in r.json() if n["name"] == package_name and n["owner"] in kwds["conda_ensure_channels"]
         )
-        return sorted(search_results, key=packaging.version.parse, reverse=True)[0]
+        return sorted(search_results, key=parse_version, reverse=True)[0]
 
     target = conda_util.CondaTarget(package_name)
     best_search_results = conda_util.best_search_result(target, conda_context=conda_context)
@@ -289,7 +302,7 @@ def _update_wf(config: "LocalGalaxyConfig", workflow_id: str, instance: bool = F
 def get_newest_tool_id(tool_ids: List[str]) -> str:
     return sorted(
         tool_ids,
-        key=lambda n: packaging.version.parse(n.split("/")[-1]),
+        key=lambda n: parse_version(n.split("/")[-1]),
     )[-1]