updatecaches: also warm the tags caches

Resolving any name requires the tags cache to be warm. We make sure that `hg
debugupdatecache` warm the tag cache entry too.

mercurial/localrepo.py

@@ -2095,6 +2095,10 b' class localrepository(object):'
             for ctx in self['.'].parents():
                 ctx.manifest()  # accessing the manifest is enough
 
+            # accessing tags warm the cache
+            self.tags()
+            self.filtered('served').tags()
+
     def invalidatecaches(self):
 
         if r'_tagscache' in vars(self):

tests/test-debugcommands.t

@@ -541,6 +541,8 b' Test cache warming command'
   $ hg debugupdatecaches --debug
   updating the branch cache
   $ ls -r .hg/cache/*
+  .hg/cache/tags2-served
+  .hg/cache/tags2
   .hg/cache/rbc-revs-v1
   .hg/cache/rbc-names-v1
   .hg/cache/manifestfulltextcache (reporevlogstore !)