fix fastmath

Author: jpn--

ext-configs/school_escorting.yaml

@@ -1,7 +1,8 @@
 # Some data values in the spec file will refer to missing values stored
 # as NaN in the data.  This requires the `sharrow_fastmath` setting to
 # be set to `false` to avoid errors in the sharrow implementation.
-sharrow_fastmath: false
+sharrow_settings:
+  fastmath: false
 
 OUTBOUND_SPEC: school_escorting_outbound.csv
 OUTBOUND_COEFFICIENTS: school_escorting_coefficients_outbound.csv