Add license to dune-project

Author: talex5

dune-project

@@ -2,6 +2,7 @@
 (name eio-trace)
 (formatting disabled)
 (generate_opam_files true)
+(license ISC)
 (source (github ocaml-multicore/eio-trace))
 (maintainers "Thomas Leonard")
 (authors "Thomas Leonard")

eio-trace.opam

@@ -3,6 +3,7 @@ opam-version: "2.0"
 synopsis: "Trace visualisation for Eio programs"
 maintainer: ["Thomas Leonard"]
 authors: ["Thomas Leonard"]
+license: "ISC"
 homepage: "https://github.com/ocaml-multicore/eio-trace"
 bug-reports: "https://github.com/ocaml-multicore/eio-trace/issues"
 depends: [