[Fix] Allow spaces in DMARC records

Issue: #4906

lualib/plugins/dmarc.lua

@@ -240,8 +240,8 @@ local function gen_dmarc_grammar()
   lpeg.locale(lpeg)
   local space = lpeg.space ^ 0
   local name = lpeg.C(lpeg.alpha ^ 1) * space
-  local sep = space * (lpeg.S("\\;") * space) + (lpeg.space ^ 1)
-  local value = lpeg.C(lpeg.P(lpeg.graph - sep) ^ 1)
+  local sep = space * (lpeg.S("\\;") * space) + (lpeg.P(lpeg.graph - lpeg.P(',')) * lpeg.space ^ 1)
+  local value = lpeg.C(lpeg.P(lpeg.P(lpeg.graph + lpeg.space) - sep) ^ 1)
   local pair = lpeg.Cg(name * "=" * space * value) * sep ^ -1
   local list = lpeg.Cf(lpeg.Ct("") * pair ^ 0, rawset)
   local version = lpeg.P("v") * space * lpeg.P("=") * space * lpeg.P("DMARC1")