x/website: Fix link to Security Policy

[Deleplace]

At https://go.dev/project , the "security policy" link goes to https://go.dev/security/ but it would be more accurate to link to https://go.dev/security/policy

[gopherbot]

Change https://go.dev/cl/463235 mentions this issue: _content/project: fix link to the security policy

[findleyr]

SGTM -- I see that @ianlancetaylor has already reviewed.

[IanoNjuguna]

Hey @findleyr can I tackle this issue?

[findleyr]

@IanoNjuguna it looks like there is a pending CL already.

[IanoNjuguna]

@IanoNjuguna it looks like there is a pending CL already.

Alright then.