[release-branch.go1.14] doc: add Go 1.14 to release history

Change-Id: I02afbd08ce9e0cd2af8953693b9c3066f6465914
Reviewed-on: https://go-review.googlesource.com/c/go/+/220937
Reviewed-by: Carlos Amedee <[email protected]>

Author: cagedmantis

doc/contrib.html

@@ -34,6 +34,7 @@ <h3 id="release"><a href="/doc/devel/release.html">Release History</a></h3>
 <p>A <a href="/doc/devel/release.html">summary</a> of the changes between Go releases. Notes for the major releases:</p>
 
 <ul>
+	<li><a href="/doc/go1.14">Go 1.14</a> <small>(February 2020)</small></li>
 	<li><a href="/doc/go1.13">Go 1.13</a> <small>(September 2019)</small></li>
 	<li><a href="/doc/go1.12">Go 1.12</a> <small>(February 2019)</small></li>
 	<li><a href="/doc/go1.11">Go 1.11</a> <small>(August 2018)</small></li>