SECURITY.md: Add file

Add a SECURITY.md file with hints for security researchers and other
parties who might report potential security vulnerabilities.

(From meta-yocto rev: d8b84cfded9137a74ab0052ff2d7710887f29f10)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

SECURITY.md

@@ -0,0 +1,24 @@
+How to Report a Potential Vulnerability?
+========================================
+
+If you would like to report a public issue (for example, one with a released
+CVE number), please report it using the
+[https://bugzilla.yoctoproject.org/enter_bug.cgi?product=Security Security Bugzilla].
+If you have a patch ready, submit it following the same procedure as any other
+patch as described in README.md.
+
+If you are dealing with a not-yet released or urgent issue, please send a
+message to security AT yoctoproject DOT org, including as many details as
+possible: the layer or software module affected, the recipe and its version,
+and any example code, if available.
+
+Branches maintained with security fixes
+---------------------------------------
+
+See [https://wiki.yoctoproject.org/wiki/Stable_Release_and_LTS Stable release and LTS]
+for detailed info regarding the policies and maintenance of Stable branches.
+
+The [https://wiki.yoctoproject.org/wiki/Releases Release page] contains a list of all
+releases of the Yocto Project. Versions in grey are no longer actively maintained with
+security patches, but well-tested patches may still be accepted for them for
+significant issues.