Update twitter to x link in README (#1345)

Link fix Update SECURITY

<!--- Please provide a general summary of your changes in the title
above -->

<!-- Give an estimate of the time you spent on this PR in terms of work
days.
Did you spend 0.5 days on this PR or rather 2 days?  -->

Time spent on this PR:

## Pull request type

<!-- Please try to limit your pull request to one type,
submit multiple pull requests if needed. -->

Please check the type of change your PR introduces:

- [ ] Bugfix
- [ ] Feature
- [ ] Code style update (formatting, renaming)
- [ ] Refactoring (no functional changes, no api changes)
- [ ] Build related changes
- [ ] Documentation content changes
- [ ] Other (please describe):

## What is the current behavior?

<!-- Please describe the current behavior that you are modifying,
or link to a relevant issue. -->

Resolves #<Issue number>

## What is the new behavior?

<!-- Please describe the behavior or changes that are being added by
this PR. -->

-
-
-

<!-- Reviewable:start -->
- - -
This change is [<img src="https://reviewable.io/review_button.svg"
height="34" align="absmiddle"
alt="Reviewable"/>](https://reviewable.io/reviews/kkrt-labs/kakarot/1345)
<!-- Reviewable:end -->

Co-authored-by: Clément Walter <clement0walter@gmail.com>

docs/SECURITY.md

@@ -6,7 +6,7 @@ If there are any vulnerabilities in **Kakarot**, don't hesitate to _report
 them_.
 
 1. Reach out in DM to the
-   [Kakarot twitter account](https://twitter.com/KakarotZkEvm) or to any of the
+   [Kakarot x (twitter) account](https://x.com/KakarotZkEvm) or to any of the
    code owners listed [here](https://github.com/orgs/kkrt-labs/people)
 
 1. Describe the vulnerability. If you have a fix, that is most welcome -- please