docs: document required optional dependency resilience4j-all (#4321)

docs: document required optional dependency `resilience4j-all` when using failover client

Author: ggivo

docs/failover.md

@@ -61,6 +61,11 @@ For more details on configuration options see sections below.
 Jedis failover support is provided by optional dependencies.
 To use failover, add the following dependencies to your project:
 ```xml
+<dependency>
+    <groupId>io.github.resilience4j</groupId>
+    <artifactId>resilience4j-all</artifactId>
+    <version>1.7.1</version>
+</dependency>
 <dependency>
     <groupId>io.github.resilience4j</groupId>
     <artifactId>resilience4j-circuitbreaker</artifactId>