Add approval for release/x.x branch (#338)

Temporary workaround for now because our CI policy requires it.

.circleci/config.yml

@@ -889,15 +889,37 @@ workflows:
             only: /^v?\d+\.\d+\.\d+$/
   release-branch:
     jobs:
-    - gradle-check-jdk11
-    - gradle-check-jdk17
-    - check-patch-file
-    - bench
-    - pkl-cli-macOS-amd64-release
-    - pkl-cli-linux-amd64-release
-    - pkl-cli-macOS-aarch64-release
-    - pkl-cli-linux-aarch64-release
-    - pkl-cli-linux-alpine-amd64-release
+    - hold:
+        type: approval
+    - pr-approval/authenticate:
+        context: pkl-pr-approval
+    - gradle-check-jdk11:
+        requires:
+        - hold
+    - gradle-check-jdk17:
+        requires:
+        - hold
+    - check-patch-file:
+        requires:
+        - hold
+    - bench:
+        requires:
+        - hold
+    - pkl-cli-macOS-amd64-release:
+        requires:
+        - hold
+    - pkl-cli-linux-amd64-release:
+        requires:
+        - hold
+    - pkl-cli-macOS-aarch64-release:
+        requires:
+        - hold
+    - pkl-cli-linux-aarch64-release:
+        requires:
+        - hold
+    - pkl-cli-linux-alpine-amd64-release:
+        requires:
+        - hold
     when:
       matches:
         value: << pipeline.git.branch >>