updates: add update barriers for N-2 (F32) for key rotation

This update barrier is pretty much useless because of
coreos/fedora-coreos-tracker#749, but we
decided to put them in place anyway just to keep following the process.

As far as the process goes. See past discussion on this topic:

- coreos/fedora-coreos-tracker#480 (comment)
- https://docs.fedoraproject.org/en-US/fedora-coreos/update-barrier-signing-keys/

updates/next.json

@@ -13,6 +13,14 @@
         }
       }
     },
+    {
+      "version": "32.20200923.1.0",
+      "metadata": {
+        "barrier": {
+          "reason": "https://docs.fedoraproject.org/en-US/fedora-coreos/update-barrier-signing-keys/"
+        }
+      }
+    },
     {
       "version": "33.20201020.1.0",
       "metadata": {

updates/stable.json

@@ -20,6 +20,14 @@
         }
       }
     },
+    {
+      "version": "32.20201104.3.0",
+      "metadata": {
+        "barrier": {
+          "reason": "https://docs.fedoraproject.org/en-US/fedora-coreos/update-barrier-signing-keys/"
+        }
+      }
+    },
     {
       "version": "33.20201201.3.0",
       "metadata": {

updates/testing.json

@@ -36,6 +36,14 @@
         }
       }
     },
+    {
+      "version": "32.20201104.2.0",
+      "metadata": {
+        "barrier": {
+          "reason": "https://docs.fedoraproject.org/en-US/fedora-coreos/update-barrier-signing-keys/"
+        }
+      }
+    },
     {
       "version": "33.20201116.2.0",
       "metadata": {