only run tests with opam 2.2 or higher to avoid resolution problems

xdge.opam

···
   "odoc" {with-doc}
   "alcotest" {with-test & >= "1.7.0"}
 ]
+x-maintenance-intent: ["(latest)"]
 build: [
-  ["dune" "subst"] {dev}
-  [
-    "dune"
-    "build"
-    "-p"
-    name
-    "-j"
-    jobs
-    "@install"
-    "@runtest" {with-test}
-    "@doc" {with-doc}
-  ]
+  [ "dune" "subst" ] {dev}
+  [ "dune" "build" "-p" name "-j" jobs "@install" ]
+  [ "dune" "build" "-p" name "-j" jobs "runtest" ] {with-test & opam-version >= "2.2" }
+  [ "dune" "build" "@doc" ] {with-doc}
 ]
-x-maintenance-intent: ["(latest)"]

xdge.opam.template

···
+build: [
+  [ "dune" "subst"                                ] {dev}
+  [ "dune" "build" "-p" name "-j" jobs "@install" ]
+  [ "dune" "build" "-p" name "-j" jobs "runtest"  ] {with-test & opam-version >= "2.2"}
+  [ "dune" "build" "-p" name "-j" jobs "@doc"     ] {with-doc}
+]