cext: increment the `parsers` module version

We introduced a new `slicechunktodensity` method to the index.

mercurial/cext/parsers.c

@@ -713,7 +713,7 b' void dirs_module_init(PyObject *mod);'
 void manifest_module_init(PyObject *mod);
 void revlog_module_init(PyObject *mod);
 
-static const int version = 11;
+static const int version = 12;
 
 static void module_init(PyObject *mod)
 {

mercurial/policy.py

@@ -69,7 +69,7 b' def _importfrom(pkgname, modname):'
     (r'cext', r'bdiff'): 3,
     (r'cext', r'mpatch'): 1,
     (r'cext', r'osutil'): 4,
-    (r'cext', r'parsers'): 11,
+    (r'cext', r'parsers'): 12,
 }
 
 # map import request to other package or module