[fix] Fix invalid specifier in test

Pinning zc.buildout = >.1 is now invalid, so use >0.1 instead.

src/zc/buildout/tests/test_all.py

@@ -2893,12 +2893,12 @@ def wont_downgrade_due_to_prefer_final():
     ... [buildout]
     ... parts =
     ... [versions]
-    ... zc.buildout = >.1
+    ... zc.buildout = >0.1
     ... ''')
     >>> [str(l.split('= >', 1)[1].strip())
     ...        for l in system(buildout+' -vv').split('\n')
     ...        if l.startswith('zc.buildout =')]
-    ['.1']
+    ['0.1']
 
     >>> write('buildout.cfg',
     ... '''