Add John to (more) license CODEOWNERS

.github/CODEOWNERS

@@ -1,9 +1,11 @@
 /crates/core/src/db/datastore/traits.rs @cloutiertyler
 /rust-toolchain.toml @cloutiertyler
-LICENSE @cloutiertyler
-LICENSE.txt @cloutiertyler
-/LICENSE.txt @cloutiertyler @jdetter
-/licenses/ @cloutiertyler
+
+# These license files are all covered by the `CODEOWNERS check` CI check as well
+LICENSE @cloutiertyler @jdetter
+LICENSE.txt @cloutiertyler @jdetter
+/licenses/ @cloutiertyler @jdetter
+
 /crates/client-api-messages/src/websocket.rs @centril @gefjon
 
 /crates/cli/src/ @bfops @cloutiertyler @jdetter

tools/ci/src/codeowners_check.rs

@@ -228,6 +228,40 @@ diff --git a/LICENSE.txt b/LICENSE.txt
             assert!(!diff_only_changes_version_or_date(diff));
         }
 
+        #[test]
+        fn rejects_entirely_added_license_file() {
+            let diff = "\
+diff --git a/licenses/new.txt b/licenses/new.txt
+new file mode 100644
+index 0000000..1111111
+--- /dev/null
++++ b/licenses/new.txt
+@@ -0,0 +1,3 @@
++Licensed Work:        SpacetimeDB 2.4.0
++Change Date:          2031-06-01
++New license term
+";
+
+            assert!(!diff_only_changes_version_or_date(diff));
+        }
+
+        #[test]
+        fn rejects_entirely_removed_license_file() {
+            let diff = "\
+diff --git a/licenses/old.txt b/licenses/old.txt
+deleted file mode 100644
+index 1111111..0000000
+--- a/licenses/old.txt
++++ /dev/null
+@@ -1,3 +0,0 @@
+-Licensed Work:        SpacetimeDB 2.3.0
+-Change Date:          2031-05-26
+-Old license term
+";
+
+            assert!(!diff_only_changes_version_or_date(diff));
+        }
+
         #[test]
         fn rejects_non_version_license_edit() {
             let diff = "\