SECURITY: Drop "patch level" from the supported version number list

This commit drops the "patch level" from the supported version numbers
listed in the security policy document because:

1. It currently does not convey any meaningful information (simply set
   to "0") and is really unnecessary because the support status is
   defined at the "minor" version level.

2. Updating the security policy document whenever there is a new "patch
   release" is arguably too noisy and does not add much value.

(cherry picked from commit fe8c1fb)

Original-Signed-off-by: Stephanos Ioannidis <stephanos.ioannidis@nordicsemi.no>
GitOrigin-RevId: fe8c1fb
Change-Id: Iaa5a24942f45bf42c0447868882f6769628c1d4f
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/zephyr/+/4287509
Commit-Queue: Al Semjonovs <asemjonovs@google.com>
Reviewed-by: Al Semjonovs <asemjonovs@google.com>
Tested-by: Al Semjonovs <asemjonovs@google.com>
Tested-by: Keith Short <keithshort@chromium.org>
Tested-by: CopyBot Service Account <copybot.service@gmail.com>
Reviewed-by: Keith Short <keithshort@chromium.org>

.github/SECURITY.md

@@ -8,12 +8,12 @@ updates:
   - The most recent release, and the release prior to that.
   - Active LTS releases.
 
-At this time, with the latest release of v3.3.0, the supported
+At this time, with the latest release of v3.3, the supported
 versions are:
 
-  - v2.7.0: Current LTS
-  - v3.2.0: Prior release
-  - v3.3.0: Current release
+  - v2.7: Current LTS
+  - v3.2: Prior release
+  - v3.3: Current release
 
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