Upgrade to RxJava 3.1.12

Closes gh-10

Author: rainboyan

gradle/libs.versions.toml

@@ -13,7 +13,7 @@ junit-platform = "1.11.4"
 objenesis = "3.4"
 rxjava = "1.3.8"
 rxjava2 = "2.2.21"
-rxjava3 = "3.1.11"
+rxjava3 = "3.1.12"
 slf4j = "2.0.17"
 spock = "2.3-groovy-4.0"
 spring-framework = "6.2.11"