release 0.7.9 (#78)

* Speed improvements.

After introduction of introspection the plugin became significantly slower.
This commit introduces several optimizations to bring the speed back up.

* Add relevant documentation and tests.

types.go

@@ -73,6 +73,7 @@ type TraefikOidc struct {
 	initComplete               chan struct{}
 	limiter                    *rate.Limiter
 	tokenBlacklist             CacheInterface
+	tokenTypeCache             CacheInterface // Cache for token type detection results
 	headerTemplates            map[string]*template.Template
 	sessionManager             *SessionManager
 	tokenCleanupStopChan       chan struct{}