Update link to spidermonkey (#702)

Author: big-r81

src/install/unix.rst

@@ -146,7 +146,7 @@ You should have the following installed:
 * `Erlang OTP (20.x >= 21.3.8.5, 21.x >= 21.2.3, 22.x >= 22.0.5, 23.x, 24.x) <http://erlang.org/>`_
 * `ICU                          <http://icu-project.org/>`_
 * `OpenSSL                      <http://www.openssl.org/>`_
-* `Mozilla SpiderMonkey (1.8.5, 60, 68, 78) <https://developer.mozilla.org/en-US/docs/Mozilla/Projects/SpiderMonkey>`_
+* `Mozilla SpiderMonkey (1.8.5, 60, 68, 78) <https://spidermonkey.dev/>`_
 * `GNU Make                     <http://www.gnu.org/software/make/>`_
 * `GNU Compiler Collection      <http://gcc.gnu.org/>`_
 * `libcurl                      <http://curl.haxx.se/libcurl/>`_