Fix wrong versioning handling in plugins.py

Due to `last_*` being 0, versioning handling was wrong when rendering the
documentation as this create a version 0.0.0 in the file version.json.

This commit fix this issues by setting `last_*` variables to `-1` and adding a
small test to better handle versioning of the documentation.

templates/docs/_data/plugins.py

@@ -810,9 +810,9 @@ def update_version(env: dict) -> None:
         return
     git_repo = git.Repo(search_parent_directories=True)
     mike_version = list()
-    last_major = 0
-    last_minor = 0
-    last_patch = 0
+    last_major = -1
+    last_minor = -1
+    last_patch = -1
     for i_tag in git_repo.tags:
         i_tag = yaml.dump(i_tag.path)
         i_tag = re.sub(".*v", "", i_tag).split(".")
@@ -820,29 +820,31 @@ def update_version(env: dict) -> None:
         minor = int(i_tag[1])
         patch = int(i_tag[2])
         if major > last_major:
-            mike_version.append(
-                {
-                    "version": "{}.{}".format(last_major, last_minor),
-                    "title": "{}.{}.{}".format(
-                        last_major, last_minor, last_patch
-                    ),
-                    "aliases": [],
-                }
-            )
+            if last_major >= 0:
+                mike_version.append(
+                    {
+                        "version": "{}.{}".format(last_major, last_minor),
+                        "title": "{}.{}.{}".format(
+                            last_major, last_minor, last_patch
+                        ),
+                        "aliases": [],
+                    }
+                )
             last_major = major
-            last_minor = 0
+            last_minor = -1
         if minor > last_minor:
-            mike_version.append(
-                {
-                    "version": "{}.{}".format(last_major, last_minor),
-                    "title": "{}.{}.{}".format(
-                        last_major, last_minor, last_patch
-                    ),
-                    "aliases": [],
-                }
-            )
+            if last_minor >= 0:
+                mike_version.append(
+                    {
+                        "version": "{}.{}".format(last_major, last_minor),
+                        "title": "{}.{}.{}".format(
+                            last_major, last_minor, last_patch
+                        ),
+                        "aliases": [],
+                    }
+                )
             last_minor = minor
-            last_patch = 0
+            last_patch = -1
         if patch > last_patch:
             last_patch = patch
     mike_version.append(