Add WEAVIATE_138 version.

Author: jfrancoa

.github/workflows/main.yaml

@@ -28,7 +28,8 @@ env:
   WEAVIATE_134: 1.34.19
   WEAVIATE_135: 1.35.18
   WEAVIATE_136: 1.36.12
-  WEAVIATE_137: 1.37.1-4e61e26.amd64
+  WEAVIATE_137: 1.37.5
+  WEAVIATE_138: 1.38.0-rc.0-461bcf7.amd64  #TODO: change to 1.38.0 when released
 
 jobs:
   lint-and-format: