Add model from older versions of caarlos0/env

Co-authored-by: Owen Mansel-Chan <62447351+owen-mc@users.noreply.github.com>

Author: egregius313

go/ql/lib/ext/github.com.caarlos0.env.model.yml

@@ -6,6 +6,7 @@ extensions:
       - ["github.com/caarlos0/env", "", False, "Parse", "", "", "Argument[0]", "environment", "manual"]
       - ["github.com/caarlos0/env", "", False, "ParseAs", "", "", "ReturnValue[0]", "environment", "manual"]
       - ["github.com/caarlos0/env", "", False, "ParseAsWithOptions", "", "", "ReturnValue[0]", "environment", "manual"]
+      - ["github.com/caarlos0/env", "", False, "ParseWithFuncs", "", "", "Argument[0]", "environment", "manual"]
       - ["github.com/caarlos0/env", "", False, "ParseWithOptions", "", "", "Argument[0]", "environment", "manual"]
   - addsTo:
       pack: codeql/go-all