Update clj-http

[mping]

Please update clj-http, the old version is throwing an error:

Caused by: java.lang.NoClassDefFoundError: IllegalName: compile__stub.clj_http.headers.clj-http.headers/HeaderMap
 at java.lang.ClassLoader.preDefineClass (ClassLoader.java:654)
    java.lang.ClassLoader.defineClass (ClassLoader.java:761)
    java.lang.ClassLoader.defineClass (ClassLoader.java:642)
    clojure.lang.DynamicClassLoader.defineClass (DynamicClassLoader.java:46)
    clojure.lang.Compiler$NewInstanceExpr.compileStub (Compiler.java:7903)
    clojure.lang.Compiler$NewInstanceExpr.build (Compiler.java:7768)
    clojure.lang.Compiler$NewInstanceExpr$DeftypeParser.parse (Compiler.java:7678)