fix opam install ppx_expect

`ppx_expect` uses Jane Street-style opam versions like `v0.17.2`, not
`0.17.2`

Author: aspeddro

dune-project

@@ -91,4 +91,4 @@
  analysis
  dune
  (ppx_expect
-  (and :with-test (= 0.17.2)))))
+  (and :with-test (= v0.17.2)))))

rescript-language-server.opam

@@ -13,7 +13,7 @@ depends: [
   "eio_main" {>= "1.3"}
   "analysis"
   "dune" {>= "3.17"}
-  "ppx_expect" {with-test & = "0.17.2"}
+  "ppx_expect" {with-test & = "v0.17.2"}
   "odoc" {with-doc}
 ]
 build: [