change version in walkthrough

Author: puredanger

doc/walkthrough.md

@@ -9,7 +9,7 @@ To use core.async, declare a dependency on Clojure 1.10.0 or higher and the late
 ```clojure
 {:deps
  {org.clojure/clojure {:mvn/version "1.12.0"}
-  org.clojure/core.async {:mvn/version "1.6.673"}}}
+  org.clojure/core.async {:mvn/version "1.8.741"}}}
 ```
 
 To start working with core.async, require the `clojure.core.async` namespace at the REPL:
@@ -157,4 +157,4 @@ We can combine timeout with `alts!` to do timed channel waits.  Here we wait for
       begin (System/currentTimeMillis)]
   (a/alts!! [c (a/timeout 100)])
   (println "Gave up after" (- (System/currentTimeMillis) begin)))
-```
+```

docs/walkthrough.html

@@ -6,7 +6,7 @@ <h2><a href="#getting-started" id="getting-started"></a>Getting started</h2>
 <p>To use core.async, declare a dependency on Clojure 1.10.0 or higher and the latest core.async library:</p>
 <pre><code class="language-clojure">{:deps
  {org.clojure/clojure {:mvn/version "1.12.0"}
-  org.clojure/core.async {:mvn/version "1.6.673"}}}
+  org.clojure/core.async {:mvn/version "1.8.741"}}}
 </code></pre>
 <p>To start working with core.async, require the <code>clojure.core.async</code> namespace at the REPL:</p>
 <pre><code class="language-clojure">(require '[clojure.core.async :as a :refer [&lt;!! &gt;!! &lt;! &gt;!]])