Update the readme to say what we depend on

Mostly to say that we shade ANTLR.

Author: iconara

README.md

@@ -22,6 +22,12 @@ Check the [releases page](https://github.com/burtcorp/jmespath-java/releases) fo
 
 If you don't want the Jackson implementation you can change the `artifactId` to `jmespath-core`, and if you specifically want to depend only on the Jackson implementation (if we release other implementations in the future) you can change it to `jmespath-jackson`.
 
+### Dependencies
+
+`jmespath-core` has an ANTLR based parser, but the ANTLR runtime artifact has been shaded into the `io.burt.jmespath` package to avoid conflicts with other artifacts that may depend on ANTLR.
+
+`jmespath-jackson` obviously depends on Jackson, specifically Jackson DataBind (`com.fasterxml.jackson.core:jackson-databind`).
+
 ## Basic usage
 
 ```java