_content: change nav dropdown text to "Security"

For golang/go#57972

Change-Id: Ibad8a1ffb1a63b9bb2d45daaad53bc52455d7766
Reviewed-on: https://go-review.googlesource.com/c/website/+/483777
Commit-Queue: Hyang-Ah Hana Kim <hyangah@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Hyang-Ah Hana Kim <hyangah@gmail.com>
Auto-Submit: Julie Qiu <julieqiu@google.com>
Reviewed-by: Jamal Carvalho <jamal@golang.org>
Run-TryBot: Julie Qiu <julieqiu@google.com>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
Reviewed-by: Julie Qiu <julieqiu@google.com>
diff --git a/_content/menus.yaml b/_content/menus.yaml
index c606bb5..58ab605 100644
--- a/_content/menus.yaml
+++ b/_content/menus.yaml
@@ -8,9 +8,9 @@
       - name: Use Cases
         explanation: Stories about how and why companies use Go
         url: /solutions/use-cases
-      - name: Security Policy
+      - name: Security
         explanation: How Go can help keep you secure by default
-        url: /security/policy/
+        url: /security/
   - name: Learn
     url: /learn/
   - name: Docs