Update dependency mashumaro to v3.21 (#218)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

requirements.txt

@@ -1,2 +1,2 @@
 aiohttp==3.13.5
-mashumaro==3.20
+mashumaro==3.21