docs: fix example payload syntax

jcristau · web-flow · commit c3c56376f823 · 2024-02-08T13:43:22.000+01:00
`env` is not a list.
diff --git a/docs/howto/bootstrap-taskgraph.rst b/docs/howto/bootstrap-taskgraph.rst
@@ -151,7 +151,7 @@ support `hashes with url requirements`_:
 
    payload:
       env:
-          - PIP_DISABLE_REQUIRE_HASHES: 1
+          PIP_DISABLE_REQUIRE_HASHES: 1
 
 .. note::
 
