Bump nightly build release branch to 2.27 (#802)

Author: jdblischak

.github/workflows/nightly.yml

@@ -24,7 +24,7 @@ jobs:
       matrix:
         os: [macos-13, ubuntu-24.04]
         branches:
-          - {libtiledb: release-2.26, tiledb-py: 0.32.0}
+          - {libtiledb: release-2.27, tiledb-py: 0.33.3}
           - {libtiledb: main, tiledb-py: main}
     env:
       MACOSX_DEPLOYMENT_TARGET: 10.15