docs: update docs/core/logger.md

Co-authored-by: Sara Gerion <47529391+saragerion@users.noreply.github.com>

Author: dreamorosi

docs/core/logger.md

@@ -154,7 +154,7 @@ Key | Example
     class Lambda extends LambdaInterface {
         // Decorate your handler class method
         @logger.injectLambdaContext()
-        public async handler(_event: any, _context: any): Promise<unknown> {
+        public async handler(_event: any, _context: any): Promise<void> {
             logger.info("This is an INFO log with some context");
         }