docs: Update databuilder docs ES version reference
Per and databuilder seems to already supports ES 8.x, but there is no mention in requirements.txt
@@ -12,7 +12,7 @@ For information about Amundsen and our other services, visit the [main repositor
## Requirements
- Python >= 3.6.x
-- elasticsearch 6.x (currently it doesn't support 7.x)
+- elasticsearch 7.x
## Doc
- https://www.amundsen.io/amundsen/
