Fix `track_memory_usage` on poetry-core 1.3.x installations (#14221)

* Fix `track_memory_usage` on poetry-core 1.3.x installations

The same kind of problem as discussed in #14085:

1. we defined an extra with an underscore
2. we look it up at runtime with an underscore
3. but poetry-core 1.3.x. installs it with a dash, causing (2) to fail.

Fix by using a dash everywhere.

* Changelog

1 files changed, 1 insertions, 1 deletions

diff --git a/synapse/config/cache.py b/synapse/config/cache.py

index 2db8cfb005..eb4194a5a9 100644
--- a/synapse/config/cache.py
+++ b/synapse/config/cache.py
@@ -159,7 +159,7 @@ class CacheConfig(Config):
 
         self.track_memory_usage = cache_config.get("track_memory_usage", False)
         if self.track_memory_usage:
-            check_requirements("cache_memory")
+            check_requirements("cache-memory")
 
         expire_caches = cache_config.get("expire_caches", True)
         cache_entry_ttl = cache_config.get("cache_entry_ttl", "30m")