use sexplib0 v0.14.0 for tests (#687)

Author: tatchi

Makefile

@@ -16,7 +16,7 @@ all:
 # results in a conflict
 .PHONY: install-test-deps
 install-test-deps:
-	opam install 'menhir>20211230' cinaps 'ppx_expect>=v0.14.0' \
+	opam install 'menhir>20211230' cinaps 'ppx_expect>=v0.14.0' 'sexplib0.v0.14.0' \
 		ocamlformat.$$(awk -F = '$$1 == "version" {print $$2}' .ocamlformat) ocamlformat-rpc
 
 .PHONY: dev

jsonrpc-fiber/test/jsonrpc_fiber_tests.ml

@@ -263,7 +263,7 @@ let%expect_test "test from jsonrpc_test.ml" =
     Uncaught error when handling notification:
     { "method": "raise", "jsonrpc": "2.0" }
     Error:
-    [ { exn = "Failure(\"special failure\")"; backtrace = "" } ]
+    [ { exn = "(Failure \"special failure\")"; backtrace = "" } ]
     <opaque>
     { "id": 10, "jsonrpc": "2.0", "result": 1 }
     { "id": "testing", "jsonrpc": "2.0", "result": 2 } |}]