Update README.adoc

added note for issue folowed by compilation error:
```
zlib_tiny/CRC64 has been compiled by a more recent version of the Java Runtime (class file version 60.0), this version of the Java Runtime only recognizes class file versions up to 52.0
```

README.adoc

@@ -14,6 +14,8 @@ Add the following to your http://github.com/technomancy/leiningen[Leiningen's] `
 [net.tbt-post/zlib-tiny "0.3.1"]
 ----
 
+CAUTION: From version v0.3.1 and upward the library requires Java class versions 60.0 and newer, thus if in your needs is to use it with Java 1.8 please switch back to older (0.2.x) version of the library or try to rebuild the library locally.
+
 === Compress
 
 ==== ZLib