doc: add 1.10.8 and 1.11.5 to the releases list

Fixes #30431

Change-Id: I379e78a1c385942a19e1a10b91d732f9a73899e6
Reviewed-on: https://go-review.googlesource.com/c/164041
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

doc/devel/release.html

@@ -73,6 +73,13 @@ <h3 id="go1.11.minor">Minor revisions</h3>
 1.11.4 milestone</a> on our issue tracker for details.
 </p>
 
+<p>
+go1.11.5 (released 2019/01/23) includes a security fix to the
+<code>crypto/elliptic</code> package.  See
+the <a href="https://github.com/golang/go/issues?q=milestone%3AGo1.11.5">Go
+1.11.5 milestone</a> on our issue tracker for details.
+</p>
+
 <h2 id="go1.10">go1.10 (released 2018/02/16)</h2>
 
 <p>
@@ -138,6 +145,13 @@ <h3 id="go1.10.minor">Minor revisions</h3>
 Go 1.10.7 milestone</a> on our issue tracker for details.
 </p>
 
+<p>
+go1.10.8 (released 2019/01/23) includes a security fix to the
+<code>crypto/elliptic</code> package.  See
+the <a href="https://github.com/golang/go/issues?q=milestone%3AGo1.10.8">Go
+1.10.8 milestone</a> on our issue tracker for details.
+</p>
+
 <h2 id="go1.9">go1.9 (released 2017/08/24)</h2>
 
 <p>