Update SpecVersion (#789)

Author: MichaelMacaulay

website/pages/en/developing/creating-a-subgraph.mdx

@@ -316,7 +316,7 @@ In this configuration:
 
 ### Declared eth_call
 
-> **Requires**: [SpecVersion](#specversion-releases) >= `1.2.0`. Currently, `eth_calls` can only be declared for event handlers.
+> Note: The highest [SpecVersion](#specversion-releases) available to sync is `1.0.0`.
 
 Declarative `eth_calls` are a valuable subgraph feature that allows `eth_calls` to be executed ahead of time, enabling `graph-node` to execute them in parallel.