README: Should always use a release version branch

From 3.12 onward, there is no 3.12 version branch but only release branches 3.12.0 etc., but for 3.10 and 3.11, we should also use the release branch to avoid discrepancies between the release build and the version branch HEAD

Author: Simran-B

CIRCLECI.md

@@ -172,7 +172,7 @@ steps below.
 | string | `workflow` | `release` |
 | string | `release-type` | `arangodb` |
 | string | `docs-version` | `3.11` (the docs version folder) |
-| string | `arangodb-branch` | `3.11` (the arangodb/arangodb branch to compile) |
+| string | `arangodb-branch` | `3.11.4` (the arangodb/arangodb branch to compile) |
 | string | `arangodb-version` | `3.11.4` (updates the `versions.yaml` file) |
 
 The ArangoDB release workflow includes the following jobs: