add serial tuning lib (#2392)

TrebledJ · web-flow · commit 894a6e093e8a · 2023-01-18T05:15:30.000Z
diff --git a/repositories.txt b/repositories.txt
@@ -5528,3 +5528,4 @@ https://github.com/khoih-prog/ESP32_SC_W6100_Manager
 https://github.com/khoih-prog/ESP32_W6100_Manager
 https://github.com/lualtek/cubecell-device-lib
 https://github.com/weedmanu/Song
+https://github.com/TrebledJ/Serial-Tuning
