doc: update the minimum supported macOS version to 10.11

Update minimum macOS supported version from 10.10 to 10.11.

Updates #23011

Change-Id: Ie10c40e882c9d309ff56041d9768afc288d0204f
Reviewed-on: https://go-review.googlesource.com/c/go/+/213878
Reviewed-by: Alexander Rakoczy <alex@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Run-TryBot: Alexander Rakoczy <alex@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/doc/install.html b/doc/install.html
index 40faadb..706d66c 100644
--- a/doc/install.html
+++ b/doc/install.html
@@ -17,7 +17,7 @@
 <p>
 <a href="/dl/" target="_blank">Official binary
 distributions</a> are available for the FreeBSD (release 10-STABLE and above),
-Linux, macOS (10.10 and above), and Windows operating systems and
+Linux, macOS (10.11 and above), and Windows operating systems and
 the 32-bit (<code>386</code>) and 64-bit (<code>amd64</code>) x86 processor
 architectures.
 </p>
@@ -49,7 +49,7 @@
 <tr><td colspan="3"><hr></td></tr>
 <tr><td>FreeBSD 10.3 or later</td> <td>amd64, 386</td> <td>Debian GNU/kFreeBSD not supported</td></tr>
 <tr valign='top'><td>Linux 2.6.23 or later with glibc</td> <td>amd64, 386, arm, arm64,<br>s390x, ppc64le</td> <td>CentOS/RHEL 5.x not supported.<br>Install from source for other libc.</td></tr>
-<tr><td>macOS 10.10 or later</td> <td>amd64</td> <td>use the clang or gcc<sup>&#8224;</sup> that comes with Xcode<sup>&#8225;</sup> for <code>cgo</code> support</td></tr>
+<tr><td>macOS 10.11 or later</td> <td>amd64</td> <td>use the clang or gcc<sup>&#8224;</sup> that comes with Xcode<sup>&#8225;</sup> for <code>cgo</code> support</td></tr>
 <tr valign='top'><td>Windows 7, Server 2008R2 or later</td> <td>amd64, 386</td> <td>use MinGW (<code>386</code>) or MinGW-W64 (<code>amd64</code>) gcc<sup>&#8224;</sup>.<br>No need for cygwin or msys.</td></tr>
 </table>