Update peps/pep-0783.rst

Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>

Author: hoodmane

peps/pep-0783.rst

@@ -159,7 +159,7 @@ particular, the Pyodide ABI version is exposed via
 Package indexes
 ---------------
 
-We recommend that package indexes accept any wheel whose platform tag matches
+Package indexes SHOULD accept any wheel whose platform tag matches
 ``pyodide_[0-9]+_[0-9]+_wasm32``.