Add security scanning opt_out config for OSS/Mirrored projects

Change-Id: I73b4673e32d45512e73b509e660c5d9c3fc7606c

security_scanning.textproto

diff --git a/security_scanning.textproto b/security_scanning.textproto
new file mode 100644
index 0000000..6c90552
--- /dev/null
+++ b/security_scanning.textproto
@@ -0,0 +1,23 @@
+repo_config {
+  repo_prefix: "3p/"
+  config_rules: [
+    {
+      opt_out: {
+        reason: OPENSOURCE_MIRROR
+        comment: "Mirror of OSS repos to be used in the project"
+      }
+    }
+  ]
+}
+
+repo_config {
+  repo_name: "scripts"
+  config_rules: [
+    {
+      opt_out: {
+        reason: GOB_MIRROR
+        comment: "Mirror of spacebeaker/shodan/scripts to be used in the project"
+      }
+    }
+  ]
+}