Fixes issue with tag concatenation causing default platform to override platforms (#49)

Author: zooba

src/manage/tagutils.py

@@ -185,7 +185,7 @@ def is_core(self):
 
     def __add__(self, other):
         if isinstance(other, str):
-            return type(self)(self._company, self.tag + other)
+            return type(self)(self._company, self.tag + self.platform + other)
         return NotImplemented
 
     def match(self, pattern):

tests/test_tagutils.py

@@ -129,3 +129,9 @@ def test_tag_range_company():
     assert not TagRange(r">=Company\3.10").satisfied_by(CompanyTag("OtherCompany", "3.10"))
 
     assert TagRange("=Company\\").satisfied_by(CompanyTag("Company", "3.11"))
+
+
+def test_tag_concatenate():
+    assert CompanyTag("3.13") + "-64" == CompanyTag("3.13-64")
+    assert CompanyTag("3.13-64") + "-64" == CompanyTag("3.13-64-64")
+    assert CompanyTag("3.13-arm64") + "-64" == CompanyTag("3.13-arm64-64")