github: workflows: Add Scorecards badge

Add the OpenSSF Scorecards badge to README.rst

(cherry picked from commit c68d67a)

Original-Signed-off-by: Pedro Kaj Kjellerup Nacht <pedro.k.night@gmail.com>
GitOrigin-RevId: c68d67a
Cr-Build-Id: 8739816385130978497
Cr-Build-Url: https://cr-buildbucket.appspot.com/build/8739816385130978497
Copybot-Job-Name: zephyr-main-copybot-downstream
Change-Id: Ib8df5647b834ce4619d3448938b8f334d171bded
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/zephyr/+/5779016
Reviewed-by: Dawid Niedźwiecki <dawidn@google.com>
Tested-by: ChromeOS Prod (Robot) <chromeos-ci-prod@chromeos-bot.iam.gserviceaccount.com>
Tested-by: Dawid Niedźwiecki <dawidn@google.com>
Commit-Queue: Dawid Niedźwiecki <dawidn@google.com>

README.rst

@@ -10,12 +10,15 @@
      </p>
    </a>
 
-   <a href="https://bestpractices.coreinfrastructure.org/projects/74"><img
-   src="https://bestpractices.coreinfrastructure.org/projects/74/badge"></a>
-   <a
-   href="https://github.com/zephyrproject-rtos/zephyr/actions/workflows/twister.yaml?query=branch%3Amain">
-   <img
-   src="https://github.com/zephyrproject-rtos/zephyr/actions/workflows/twister.yaml/badge.svg?event=push"></a>
+   <a href="https://bestpractices.coreinfrastructure.org/projects/74">
+     <img src="https://bestpractices.coreinfrastructure.org/projects/74/badge">
+   </a>
+   <a href="https://scorecard.dev/viewer/?uri=github.com/zephyrproject-rtos/zephyr">
+     <img src="https://api.securityscorecards.dev/projects/github.com/zephyrproject-rtos/zephyr/badge">
+   </a>
+   <a href="https://github.com/zephyrproject-rtos/zephyr/actions/workflows/twister.yaml?query=branch%3Amain">
+     <img src="https://github.com/zephyrproject-rtos/zephyr/actions/workflows/twister.yaml/badge.svg?event=push">
+   </a>
 
 
 The Zephyr Project is a scalable real-time operating system (RTOS) supporting