Add Policy manager repo

BUG=b/73012579
TEST=Performed repo sync src/third_party/policymanager to see if the
repo gets initialized

Reviewed-on: https://cos-review.googlesource.com/c/cos/manifest/+/21350
Reviewed-by: Robert Kolchmeyer <rkolchmeyer@google.com>
Tested-by: Rayan Dasoriya <dasoriya@google.com>
Reviewed-on: https://cos-review.googlesource.com/c/cos/manifest/+/21810
Reviewed-by: Ke Wu <mikewu@google.com>
Change-Id: I7e1506dc15160795cb7dcee5b0becb461a3a3d69
Reviewed-on: https://cos-review.googlesource.com/c/cos/manifest/+/21771
diff --git a/external_full.xml b/external_full.xml
index 3568fd7..29247b7 100644
--- a/external_full.xml
+++ b/external_full.xml
@@ -95,6 +95,9 @@
   <project path="manifest" name="cos/manifest" >
       <copyfile src="LICENSE" dest="LICENSE" />
   </project>
+  <project path="src/third_party/policymanager"
+           name="cos/policymanager"
+           revision="refs/heads/release-R93" />
   <project path="src/third_party/kernel/v5.10"
            name="third_party/kernel"
            revision="refs/heads/release-R93-cos-5.10" />